Matsya Purana 274.41

274.41

pūrveṇa ṛgvedavidāvathāstāṃ yajurvidau dakṣiṇataśca śastau.
sthāpyau dvijau sāmavidau tu paścādātharvaṇāvuttaratastu kāryau .. 274.39

To the east of the Maṇḍapa two Brâhmaṇas versed in the Ṛigveda should be seated, to the south should be seated two Brâhmaṇas accomplished in the Yajurveda, two to the west knowing the Sâmaveda and two to the north versed in the Atharvaveda All those learned men should offer Homas or sacrificial libations four times in four directions by reciting the Vedic hymns on their respective altars to Gaṇeśa, Grahas, Lokapâls, Aṣṭavasu, Āditya, Marudgana, Brahmâ, Viṣṇu, Śiva, Sûrya and the Vanaspatis—39-40