Bhattacharya, B. P. Studies in the Śrautasūtras of Āśvalāyana and Āpastamba, 1978 v. 1, t.p. (Āpastamba [in rom.]) p. ii (great thinker in the field of religious studies)
His Śrautasūtram, 1983 v. 1, t.p. (Āpastamba) v. 3, p. xvi (lived in the South of India, in the country of the Andhras, not much later than 5th cent. B.C.)