Matsya Purana 58.34

58.34

rātrisūktañca raudrañca pāvamānaṃ sumaṅgalam.
japeyuḥ pauruṣaṃ sūktaṃ pūrvato bahvṛcāḥ pṛthak.. 58.33 ..

Then the knowers of the Rigveda, seated in the east, should separately mutter the formulae of Râtrisûkta, Rudrasûkta, the auspicious Pâvamânasûkta, and Puruṣasûkta; in the same way the Dvârapâlas, learned in the Yajurveda, seated in the south, should separately mutter the formulae of Indra, Rudra, Soma, Kûṣmânda, Fire (Jâtavedas), and the Sun.—33-34.