Vishnupurana 1.5.53

1.5.53

gāyatraṃ ca ṛcaś caiva trivṛtsāma rathantaram
agniṣṭomaṃ ca yajñānāṃ nirmame prathamān mukhāt //

From his eastern mouth Brahmá then created the Gayatrí metre, the Rig veda, the collection of hymns termed Trivrit, the Rathantara portion of the Sáma veda, and the Agnisht́oma sacrifice: from his southern mouth he created the Yajur veda, the Trisht́ubh metre, the collection of hymns called Panchadaśa, the Vrihat Sáma, and the portion of the Sáma veda termed Uktha: from his western mouth he created the Sáma veda, the Jayati metre, the collection of hymns termed Saptadaśa, the portion of the Sáma called Vairúpa, and the Atirátra sacrifice: and from his northern mouth he created the Ekavinsa collection of hymns, the At́harva veda, the Áptoryámá rite, the Anusht́ubh metre, and the Vairája portion of the Sáma veda.