Zvelebil, Kamil (1997), The Smile of Murugan: On Tamil Literature of South India: On Tamil Literature of South India, BRILL Academic Publishers. p. 378, ISBN90-04-03591-5 Quote: "Chart 1 literature: 1. the "Urtext" of the Tolkappiyam, i.e. the first two sections, Eluttatikaram and Collatikaram minus later interpolations, ca. 100 BC 2. the earliest strata of bardic poetry in the so-called Cankam anthologies, ca. 1 Cent. BC–2 Cent. AD."