SB 1.4.21
tatrarg-veda-dharah pailah
samago jaiminih kavih
vaisampayana evaiko
nisnato yajusam uta
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
After the Vedas were divided into four divisions, Paila Rsi became the professor of the Rg Veda, Jaimini the professor of the Sama Veda, and Vaisampayana alone became glorified by the Yajur Veda.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The different Vedas were entrusted to different learned scholars for development in various ways.