McClish & Olivelle 2012, p. xxiv: "Although the Vedas are essentially liturgical documents and increasingly mystical reflections on Vedic ritual, they are sufficiently rich and extensive to give us some understanding of what life was like at the time. The earliest of the Vedas, the Ṛgveda Saṃhitā, contains 1,028 hymns, some of which may be as old as 1500 BCE. Because the Vedic texts are the primary way in which we can understand the period between the fall of the IVC (ca 1700) and the second wave of urbanization (600 BCE), we call the intervening era of South Asian history the 'Vedic Period.'" McClish, Mark; Olivelle, Patrick (2012), "Introduction", in M. McClish; P. Olivelle (eds.), The Arthasastra: Selections from the Classic Indian Work on Statecraft, Hackett Publishing, p. xxiv, ISBN978-1-60384-903-6
Bellah 2011, p. 491 f.. Bellah, Robert N. (2011). Religion in Human Evolution: From the Paleolithic to the Axial Age (1st ed.). Belknap Press of Harvard University Press. ISBN978-0-674-06143-9.
Bellah 2011, pp. 697–698, citing Trigger (2003). Bellah, Robert N. (2011). Religion in Human Evolution: From the Paleolithic to the Axial Age (1st ed.). Belknap Press of Harvard University Press. ISBN978-0-674-06143-9.
Bellah 2011, p. 698 f.. Bellah, Robert N. (2011). Religion in Human Evolution: From the Paleolithic to the Axial Age (1st ed.). Belknap Press of Harvard University Press. ISBN978-0-674-06143-9.
Bellah 2011, p. 509, citing Olivelle (1998), pp. xii–x. Bellah, Robert N. (2011). Religion in Human Evolution: From the Paleolithic to the Axial Age (1st ed.). Belknap Press of Harvard University Press. ISBN978-0-674-06143-9.
Paul & Paul 1989, pp. 112–115, 125. Paul, Pran Gopal; Paul, Debjani (1989). "Brahmanical Imagery in the Kuṣāṇa Art of Mathurā: Tradition and Innovations". East and West. 39 (1–4): 111–143. JSTOR29756891.
Paul & Paul 1989. Paul, Pran Gopal; Paul, Debjani (1989). "Brahmanical Imagery in the Kuṣāṇa Art of Mathurā: Tradition and Innovations". East and West. 39 (1–4): 111–143. JSTOR29756891.
Tignor 2014. Tignor, Robert L. (2014). Worlds together, worlds apart: A history of the world from the beginnings of humankind to the present (4th ed.). New York: W. W. Norton & Company. ISBN978-0-393-92207-3. OCLC854609153.