Authors : Shivashankar Rao & Rami Sivan
Veda & Vedanta
Author: Rami Sivan (Hindu priest and teacher of Indian Philosophy)
Jan 23rd, 2020
Each Veda is divided into four sections each one evolving from the other.
Veda-Saṃhitas — The ‘Collections of Wisdom-Scriptures’ (saṃ-hita = placed together; veda = wisdom). They are:
- ṛg-veda —The foremost of Vedas: a collection of Illuminating Hymns to the various devas called sūktas composed by 329 Rishis (m) – 27 Rishikas (f).
- sāma-veda — Scripture of Harmonious Joyful Chants or Sāmans to be sung to certain melodies. A recast of the Rig-Veda broken up into parts and arranged for purposes of being chanted at the Soma sacrifice.
- yajur veda — the Scripture of Sacrificial Rites or the right ordaining of action. It consists principally of prayers and invocations applicable to the consecration of the utensils and materials of sacrificial worship, but also symbolic of the means by which humankind attains divinity. This Veda is divided into two parts, ‘The White – Śukla’ and ‘The Black – Kṛṣṇa’.
- atharva-veda — Scripture of the ancient Atharvans composed chiefly of mystical formulas intended to counteract disease and evil. This is where Hogwarts School of Magic and Wizardry get’s it curriculum from.
Each of these Vedas consists of the following divisions:
- Saṁhitās – Sūktas or mantras section.
- Brāhmaṇas — Works in prose dealing with Vedic ritual its complex interpretation and elucidation, along with various legends and myths and traditional and cultural matter (brahman = prayer).
- Āraṇyakas — Philosophical prose treatises attached to the Brāhmaṇas for study by ascetics of the forest (araṇya = forest).
- Upaniṣads — Treatises in poetry and prose on spiritual and philosophical subjects – inquiry into the nature of reality, the Self, the goal of life etc. (upa-ni-ṣad = sit down near-the guru).
So the Upaṇiṣads are the final compilations of the Vedic corpus and are the most authoritative texts. These texts form the basis of main-stream Hindu philosophy which is called Vedānta = the culmination of the Vedic wisdom.
All the other three sections are only studied by a small group of elite priests. Many of the mantras and sūktas used in popular Vedic worship come from those texts and they can be regularly heard chanted in temples. But for study purposes only the Upaṇiṣads are used since they are compared to the milk of a cow (the cow itself being analogous to the Vedas).
The Bhagavad Gītā contains the essence of the Upaṇiṣads and therefore is referred to as the “cream” of the Upaṇiṣads.
Since the Upaṇiṣads are the conversations and discourses of several different sages with different opinions, they do not present a systematic philosophy, so one sage Bādarāyaṇa composed the Brahmā-sūtras in order to reconcile the conflicting and contrasting views of the various gurus.
Some folks try to link this author with the Vyāsa (compiler) of the Purāṇas but this is patently wrong since Bādarāyana mentions some views of the Buddhists which he refutes, so the Brahmā-sūtras were probably completed in their present form sometime in 400 – 450 CE.
All three great Vedānta Ācāryas – Shankara, Ramanuja and Madhva wrote commentaries on the Brahmā-sūtras to support their version of the Vedānta philosophy.
So the modern philosophical bedrock of Vedānta comprises of these three texts (Upaniṣads, Gītā and Brahmā-sūtras) known collectively as the Prasthāna-trayam.
And once again I will stress to all my gentle Paurānikas that the only verses from the Puraṇas and Itihāsas which are authoritative are those texts and statements which agree with the Prasthāna-trayam! Everything else is there for the taking or leaving.
Function of Scriptures
Jan 21st, 2020
The function of scripture known as śāstra is summed up in the sūtra – ajñāta jñāpana iti śāstra – which means “the function of scripture is to inform us about those things which we cannot figure out for ourselves using evidence and critical thinking.”
So the primary source of knowledge concerning the world we live in is obtained through observation, evidence and experimentation (pratyakṣa) and through critical and rational thinking (anumāna). These are our foundation tools for knowledge and should never be neglected. In the Gita Krishna says – buddhau śaraṇam anivicche – which means “take refuge in intelligence” – in other words use your brain!
There are three metaphysical questions which are confounding and which we can’t really figure out using evidence and rational thought and is the subject of perennial debate and argument:–
- Who am I? what is the nature of my own existential reality?
- What am I doing here? What is the nature of the reality which I inhabit and what is the purpose of life?
- What do I do now? How should I live my life in an authentic and meaningful way – what is the blueprint for a good life?
Śāstra does not tell you what to think – it guides you how to think. And it answers these three questions and above all the focus is on the last point which in the Gītā is called KARMA-YOGA.
The Mīmāṁsa sūtras (hermeneutic) declare that the primary function of all the Vedic texts is VIDHI – which is an injunction to act in a certain way – in other words prescribes the MO of DHARMA. Dharma being defined as niḥśreyasa sādhanam – the means of achieving the highest common good.
Gīta also tells us that we should always take the guidance of Śāstra in deciding what we should and should not do (tasmāt śāstra pramāṇam te kārya akārya vyavasthitau)- again the focus being on ACTION – Karma Yoga.
The Gītā is the summary and pinnacle of Śāstra and it is the only text worth studying and applying in daily life.
And what is unique to Hinduism and extremely important is that scripture (śāstra) can never override evidence (pratyakṣa) and reason (anumāna). If the scripture states something that contradicts evidence and observation and is irrational it should be rejected!
List of all Hindu (Sanatana Dharma) Scriptures and Classifications
Dec 31st, 2018
Here I am giving a synopsis of the Sanskrit Scriptures. Many of these texts named have several volumes – for example the śatapatha Brāhmaṇa has 5 volumes and the Mahābhārata 18.
The Sacred literature in the other Indian languages starting with Tamil would run into the hundreds or thousands.
Now you know why we talk of the “Ocean of Shastra”. Hindus do not have one single Book – we have a library.
WHAT ARE THE VEDAS ?
Author: Shivashankar Rao
The basic scriptures of Sanatana dharma, the Vedas contain all ideas pertaining to Vedanta, Jnaana,Bhakti etc., These consist of a vast body of esoteric knowledge concerning spiritual values. The date of Rig-Veda(the earliest) is generally agreed to be around 10000 BC.(some estimate this to be around 25000 years back also). Vedas are also called Shrutis (what is heard) and are handed down to posterity by oral tradition. Hymns used to invite the deities to the sacrifices (Yajnas) are in Rigveda. Liturgical parts form Yajurveda. Musical chants are in Saamaveda. The miscellaneous appendices and addenda are to be found in Atharva veda. Krishna Dvaipaayana(Vyaasa) is credited with the division of Vedas. He is said to have transmitted each part to his disciples- Paila, Vaishampaayana, Jaimini and Sumantu respectively. Samhita is collection of Mantras and Braahmana includes Aararanyaka and Upanishads. The Aaranyakas deal with meditations and Upanishads are philosophical treatises. Normally, Samhitas are the ones indicated by the term Vedas. The Braahmanas, Aaranyakas and the Upanishads are treated as appendages. Samhitas have further branched off into shaakhas.
Rigveda samhita is the oldest collection of sooktas. Though there were 21 shaakhas in these, only five are available now.
These are – 1. Shaakala, 2. Baaskala, Aashvalaayana, Shaankhaayana, and Maandookeya.
There are 10, 552 mantras in the 8 ashtakas and 64 adhyaayas. There are 10 mandalas, 85 anuvaakas. The topics dealt with concerns deities like Agni, Indra, Varuna etc., It also deals with the origin of universe and the nature of human beings (including secular subjects like marriages, wars etc.,). Although saguNOpaasana is predominant, it teaches monotheism and not polytheism (Eka dEvatA vaada).
The Rigveda has the following:
1. AitarEya and Kausheetaki brahmanas,
2. AitarEya and Shaankhaayana Aaranyakas,
3. AitarEya and Kausheetaki Upanishads.
Mantras are in prose to facilitate in the performance of yajnas, yaagas.
There are two forms of Yajurveda.
1. Krishna yajurveda and
2. Shukla yajurveda.
Krishna yajurveda is both in prose and poetry and hence considered “not pure”. Being the older one, It is also considered as more difficult to understand hence “black”. Shukla yajurveda (being a later version) is in poetic form. Krishna yajurveda which had 85 shaakhas has only four available now. These are Taittareeya, Maitraayaneeya, Katha and Kapisthala. The Taittareeya samhita is the one generally available in South India.This has 7 kaandas, 44 prapaatakas and 651 mantras. It deals mainly with yaagas like Paurodaasha, Yaajamaana, VaajapEya, Darshapoornamaasa and Somayaagas. Taittareeya Brahmana, Taittareeya Aaranyaka and Taittareeya Upanishad, Katopanishad ae all associated with the Taittareeya samhita.
The Shukla Yajurveda samhita is also known as VaajasanEya samhita (Yaajnavalkya’s). Only two shaakhas are now available for this- The Kaanva and Maadhyaandina. Kaanva is more prevalent in the south India and the Maadhyaandina is more used in the North.
The mantras here are called Saamans and have svaras (musical scales). Indian classical music took its birth here. Although there are 9 brahmanas attached to this, Taandya maha braahmana is the most important. Talavakaara or Jaimineeya Aaranyaka is the only aaranyaka of this veda. ChaandOgya and KEna are two Upanishads attached to this Veda.
ATHARVA VEDA SAMHITA
Atharva veda is also called Brahma veda. It deals with diseases and their cure, rites for long life, rites for fulfilling other desires, construction of buildings, commerce and trade, administration etc., There are 6077 mantras spread over 20 kaandas and 4 prapaatakas. There are no Aaranyakas for this veda and there is one Braahmana- the Gopatha brahmana. The Prashnopanishat, Mundaka and Maanddokya are the Upanishats belonging to this Veda.
It is difficult to understand the Vedas because of the archaic language and terminology. The six Vedangas should help in the understanding. These are Sheeksha, Vyaakarana, Chandas, Nirukta, JyOtisha and Kalpa. These deal with the modes of chanting, grammar, details of meters of vedic poetry, meanings and explanations of words etc., There are several commentaries and Saayanaachaarya’s commentary is considered the best among them.
APOURUSHEYATVA OF VEDAS
Here is something for those interested in the apourusheyatva of the Vedas. It would be interesting to hear about some other proof on the subject. Regarding the antiquity of the Vedas, there can be two view points. Hindu writers went to one extreme in ignoring history altogether while modern westerners go to the other extreme making it too much in their historical treatment. Anyway, I feel we should be interested in eating the fruit of the tree instead of digging at the roots. But history is essential to know the doctrines of Hinduism belonging to the Vedic period and what doctrines belong to the later Puranic period. It is also necessary to understand what made the dharma strong and what brought in its downfall. Just to take one example to show the developmental process, we know that Vedic deities are usually enumerated as 33- 8 Vasus, 11 Rudras, 12 Aadityas, Indra and Prajaapati. Many of these are no longer considered important.
However, considering the sanctity of the Vedas and the impatience of the conservatives not to even consider any views against the concept of APOURUSHEYATVA, we have also agreed that no proof can be given for such belief. In the direction of finding some proof of it, I invite you to see the paper by PETER RASTOR, “PHONETIC SYMMETRIES IN THE FIRST HYMN OF THE RIGVEDA” wherein he discusses the symmetries, self organisation and the doctrine of the impersonal origin of the Vedic Hymns.
What is Vedanta ?
November 12, 2018
Vedanta means the end portion of the Vedas. These contain the essence of the Vedas. Although there are six systems of philosophy which accept the authority of the Vedas, Meemamsa and Vedanta have direct connections with the Vedas. Vedanta tries to make out a coherent philosophy of Brahman from the apparent conflicting statements of the Upanishads. Upanishads deal with the ultimate problems of life.
The Vedanta system is based on three canonical works (Prasthana traya) – shruti prasthana (Upanishads), Brahmasootras(Nyaya prasthana) and Bhagavadgita (smriti prasthana). The edifice of the Vedanta system depends mainly on the Upanishads.
Badarayana attempted to reinterpret and reorganize the teachings of the Upanishads to get a more coherent look and the result was the Brahmasootras (also called Vedantasutras). These deal with the Brahman as described in the Upanishads in all its aspects. The Vedanta philosophy based on Upanishads has held sway over the centuries.
Several great scholars have given their own commentaries on these. Some of them are:
- Shankara, (Advaitha)
- Bhaskara, (Bhedaabheda)
- Ramanuja, ,(Vishishtaadvaitha)
- Madhva, (dvaita)
- Nimbarka, (Dvaitadvaita)
- Shrikantha, (Shaiva vishistaadvaitha),
- Shreepati (Bheda-bhedaatmaka vishistaadvaita)
- Vallabha (Shuddhaadvaita)
- Shuka (Bhedavaada)
- Vijnaanabhikshu (Aatma brhmaikya bhedavaada)
- Baladeva (achintya bhedaabheda).
The philosophy of the upanishads has influenced all the important aspects of Sanatana Dharma and culture.
SHOULD THE SACRED KNOWLEDGE OF VEDAS BE KEPT SECRET ?
The term veda is derived from the root vid which means “to know”. Conventionally, it is the samhitha that is indicated by the term veda. The brahmanas, Aranyakas and the upanishads are more like its appendages. These samhitas had to be committed to memory and were passed on orally from generation to generation. The chanting modes are the pada paata, kramapaata, jataapaata and the ghanapaata. Due to the archaic form of language and terminology, it is difficult to understand the vedas. The six vedangas help in understanding them. These are – Shikshaa, VyaakaraNa, Chandas, Nirukta, Jyothisha and Kalpa. There are several commentaries to help in understanding the vedic literature. In addition to the exhaustive work by SAayanaachaaarya, the others who have done some work in this direction include Skandaswami, venkatamadhava, Bhatta Bhaskara and Ananda theertha. It is for the thinking people to consider whether this vast body of knowledge should be hidden from a majority of the population which may ultimately lead to the evaporation of the treasure or to open the gates of knowledge to all those who are interested and are capable of learning with sincerity and devotion.
PURANA, what are they?
Our old beliefs and culture are the main reasons for whatever has remained with us on honesty, purity, liberal attitude, sacrificial nature, chivalry etc. Truth and good conduct are our basic nature. “Yadbhootahitamatyantam tatsatyamiti dhaarana”. To remain peaceful without either hate or attachment and to do good to every one is dharma. The basis for dharma is the Vedas.- VedOkhilam Dharmamoolam (Manu 2.1), VedO dharmamoolam (Goutama dharmasootras (1.1).
Vedas are also called shruthis (heard). Vedangas help in understanding the Vedas. Shikshaa, Vyakarana, Chandas, Nirukta, Jyothisha and Kalpa are the six Vedangas. Vedas are divided into three groups- Karmakaanda, Upaasanaakaanda and Jnaanakaanda. Based on the Vedas, several Smrithis have come into existence to make the contents simpler and easy to understand and follow. These smrithis are the basis for Dharmasastras, Mahakaavyaas, Puranas, Agamas or methods of worship etc. Smrithis consolidate the rules and regulations necessary to regulate the society from time to time. As society grows and changes, smrithis should also change. Otherwise, it will be like forcing a dress stitched for a baby on a grown up man. That is how the smrithis written by Manu, Yajnavalkya or Parashara have become outdated. (The Indian Constitution is the smrithi now being followed in our country).
Puranas and epics contain stories based on history. However, major portions of these are because of the creative ability of the authors/poets. The main purpose of the puranas is to create an atmosphere where people realize how God has helped in uplifting the humanity.
WHO WROTE THEM ?
PurANa literally means 1. purA bhavam (ancient narratives), and 2. purA api navam (that which is new even though old). The words purana and itihAsa occur in ancient Atharvaveda and shathapatha brahmana and in Upanishads like Brihadaaranyaka and chaandogya. It is possible that puranas are as old as Vedas themselves. (Sometimes they are referred to as purana smhitha).
Though traditionally the authorship is attributed to Vedavyasa, he might have compiled the then existing tales, anecdotes, metrical songs into a comprehensive samhitha. His disciples and their disciples might have composed more detailed works to bring them to the present form. (Vyasa imparted it to his disciple Soota Romaharshana who taught it to KAshyapa, SAvarNi and ShAmasapAyana. Finally and gradually, the number of puranas got fixed at eighteen (also called mahapuranas).
These eighteen puranas generally accepted are:-
- Bhaagavatha purana,
- Bhavishya purana,
- Brahma purana,
- Bramaanda purana,
- Brahmavaivartha purana,
- Garuda purana,
- Koorma purana,
- Linga purana,
- MaarkanDeya purana,
- Matsya purana,
- Naaradeeya purana,
- Padma purana,
- Varaaha purana,
- Vaayu purana and
- Vishnu purana.
We may now see a gist of the contents of these puranas one by one. Then we may discuss on the antiquity of the puranas, their general characteristics, their evolution and growth, the recurrent topics in them, their ethics etc. After this, we may proceed to discuss the upa puranas (which are also 18 in number).
AGNIPURANA :Agni told this to Vasishta. It contains descriptions of Rama and Krishna (Ramayana and Mahabharata) in addition to details about the other avatharas of Vishnu. It also gives rules of worship of various deities, installation of idols in temples, Jyotishya, Architecture, medicine human physiology and various other such subjects.
BHAGAVATHA PURANA: SRIMADBHAGAVATHA is the most well known of the puranas. Sage Shuka tells the story of Krishna to king Pareekshit. Although it contains stories of the other avatharas of Vishnu, the emphasis is on the life of Krishna. It explains the cosmic form of God and how the universe is created, the story of Jaya and Vijaya and how they had to take three janmas as Hiranyakashipu- Hiranyaaksha etc., the story of Prahlada’s devotion, Story of Kapila, Daksha yajna and its destruction by Rudra, stories of Dhruva, Jadabharatha etc., Stories of Gangaavatharana, Tripura samhaara, samudra mathana etc. Krishnaavathaara details are found in the tenth chapter and the eleventh contains the famous Uddhavageetha.
There is a vivid description of the present Kaliyuga. There are a number of commentaries on this Purana and is considered the most popular among all the puranas.
BHAVISHYA PURANA: Some scholars consider the second part of this purana as an independent purana and call it the Bhavishyottara purana. Among the several topics dealt with in this purana mention could be made of the shodasha samskaaras, rules for the study of Vedas, Vrathas and kaamya karmas, varnaashrama dharma, worship of Soorya and snakes, creation of the earth and the world, etc. There is a description of the good conduct one must emulate. This purana is considered as a pointer and indication of the future and so, it is called the Bhavishya purana.
BRAHMAPURANA: Shrines at holy places like Puri, Konark and Bhuvaneswar are described in addition to the portions of Mahabharata, and some other puranas like Markandeya purana etc. Story of Daksha’s sacrifice, story of Krishna, description of certain avatharas like Varaha, Nrisimha etc., are the others dealt with in this. It also deals with creation of the world and description of the sapta dveepas.
BRAHMAANDAPURANA: It deals with creation of brahmaanda (cosmic egg) and description of Bharatavarsha. The other contents are about shraadhdhas etc in addition to stories of Bhagiratha, Parashurama, Dhanvantri etc. A very important portion of this purana is the LalithOpaakhyaana in forty chapters which includes the famous Lalitha sahasranama. The whole purana is in four parts.
BRAHMAVAIVARTA PURANA: Vivarta or appearence is a term used in the advaita vedanta. This purana is Krishna centric. It describes Durga, Lakshmi, Saraswati etc., as evolved from Moolaprakriti as per the desire of Krishna. Shree Krishna janma kaanda describes the story of Krishna and Radha. There are stories of Shanmukha and Ganesha. There are some mundane subjects like Ayurveda, rules for building construction, bathing in Ganga and its benifits, greatness of Tulasi, code of conduct of women etc.
GARUDAPURANA: We all know that this purana is read when some one in the family passes away. It is said that this purana was taught by Vishnu himself to Garuda. While the first part deals with stories from the two epics- Mahabharatha and Ramayana- in addition to certain medicines and uses of precious stones etc., the second part deals with the prethakalpa- the journey of Jeeva after death. It suggests that moksha or liberation from the cycle of births and deaths is through devotion to Vishnu.
KOORMAPURANA: This is believed to have been taught by Vishnu in his Koormaavathaara to sage Naarada. It describes the chaaturvarnas and how the prakriti evolved as the world. Stories of Manu, Daksha, Vaamana, Yaduvamsha, Kaashi and Prayaaga etc. It also describes certain praayaschittas. It deals with Pralaya also.
LINGAPURANA: The five aspects of Shiva- Sadyojaata, Vaamadeva, Tatpurusha, Aghora and Eeshaana are described. The story of Shiva appearing as a huge pillar of fire to Vishnu and Brahma is dealt with. Stories of Dadheechi, Vyasa, Nandi, Sooryavamsha and chandravamsha kings, Kaashi etc., are the others. Shiva’s eight forms, Shiva panchaakshari mantra and the meditation of Shiva after establishing shivalinga, the mruthyunjaya mantra are the other contents.
MAARKANDEYA PURANA: This contains the teachings of Markandeya to Krowshtuki. The most well known portion of this purana is the Durgasaptashati or the Devi mahatme. In addition to the subjects of manvantaras etc., it deals with the stories of Harishchandra, Kartaveeryaarjuna etc. Karma and its usefulness and some portions of Yoga are also dealt with. In this purana, instead of shiva and vishnu, other deities like Indra, Agni, Surya etc are given importance.
MATSYAPURANA: This is supposed to have been taught by Vishnu in his Matsyaavathaara. Stories of Kacha- Devayaani, Yayathi- Puru, etc., are described. Various Vratas, daanas(gifts), holy places and rivers are also mentioned. Even mundane subjects like Building construction are explained.
Naarada Purana: This is believed to be the teachings of Naarada to Sanaka and other rishis. Religious rites, devotion to God, duties of people of each varna and Aashrama are detailed. There is a different version of Lalthaasahasranaama which is not popular. Fasting on the eleventh day of each paksha of a month (Ekaadashi) and its benefits is given importance.
PADMAPURANA: This deals with a number of subjects and it is in five parts. There are several stories and important rivers and pilgrimage centres are described. Several vrathas are found in this purana. Several sahasranaamas are also mentioned.
SKAANDA PURANA: This purana was originally taught by Shivamahadeva to his consort Parvathi. It contains many stories. It gives a detailed description of Bhaaratavarsha of those days. In addition to the various forms of Shivalingas and the meditation thereof, the now famous Sathyanarayana vratha is also described.
VAAMANAPURANA: The incarnations of Vishnu- mainly as a Vaamana- is described in addition to the mention of other deities like Shiva, Ganapati and Soorya. The doctrine of Karma is explained. An important portion of this purana is the story of Gajendra moksha.
VARAAHA PURANA: This is supposed to have been given by Vishnu to Bhoodevi in his Varaaha roopa, It provides details of the theory of Karma, Shraadhdhas , Ashoucha etc. An important portion of this purana is the Nachiketopaakhyaana which deals with heaven and hell.
VAAYU PURANA: Gayaa, the famous place known for shraadhdhas is described in addition to the details of the shraaddha ceremonies. The science of musicology is a part of this purana. These are in addition to the other usual descriptions of several kings and rishis etc.
VISHNU PURANA: In addition to the other usual descriptions of creation, there are stories of Dhruva, Prahlaada etc. The Kalidosha is also dealt with. The stories of Raama and Krishna are also described. It is important to note that Vishnu here is not one of the thrimoorthies, but the origin of all the three- the para Brahma.
Bhaktimaarga is given utmost importance.
We should note that the puranas with their simplicity of presentation and language have helped in the preservation of our philosophy and dharma over a long period as they are easily accessible to the common man. However, it should be remembered that wherever there is any ambiguity or conflicts with the other texts of shrutis and smrities, what the shruthi says becomes final and not what the puranas or smrities say.
Here is a list of the reference materials on the subject.
1. Allen.W. Sidney. 1953. PHONETICS IN ANCIENT INDIA. London: Oxford University Press.
2. Electroencepholography and clinical neurophysiology 13, and suppliment 7.
3. Brandmuller,Josef; claus,Reinhart 1982 “Symmetry -its significance in science and art”Interdisciplinary Science Reviews 7/4.
4. Chalmers R et.al., 1989. Scientific research on Maharshi’s Transcendental Meditation and TM-Siddhi Programme. Colloected papers.Vols.2-4. Viodrop, Netherlands.: MVU Press.
5.Freedman, Daniel Z Supergravity and the Unification of the laws of physics.- Scientific American 238/2.
6. Macdonell, AA 1962. A Vedic reader for students. Madras: Oxford University Press.
7. Mangal Deva Shastri 1937. The Rgvedapraatishakya with commentary of Uvata, Vol.3 English translation of the text, Additional notes, Motilal Banarsidass.
8.Sarup, Lakshman 1967. The Nighantu and the Nirukta – The oldest Indian treatise on Etymology , phylology and Semantics. Delhi- Motilal Banarsidas.
There are several other references mentioned in the paper by Peter Rastor.