Vishnupurana 3.4.p6

3.4.p6

Indira-Pramati, O Maitreya, gave his Sanhita to his magnanimous son Mandukeya, which thence descended through successive generations and disciples. Vedamitra, otherwise called Sākalya, read the same Sanhita and divided it into five Sanhitas which he gave to his disciples named severally Mudgala, Goswalu, Vātsya, Sāliya and Sisira. Sākapuvni made a different classification of the original Sanhita into three and added a Nirukta (glossary) constituting a fourth. And he gave these three Sanhjtas to his three pupils, Kraunch, Vaitalaki, and Valaka. And the glossary was given to the fourth who was named Niruktakrit and who was versed in the Vedas and their various branches.