Srimad-Bhagavatam: Canto 12 - Chapter 1 - Verse 78
Sanskrit:
उदीच्या: सामगा: शिष्या आसन् पञ्चशतानि वै ।पौष्यञ्ज्यावन्त्ययोश्चापि तांश्च प्राच्यान् प्रचक्षते ॥ ७८ ॥
ITRANS:
udīcyāḥ sāma-gāḥ śiṣyāāsan pañca-śatāni vaipauṣyañjy-āvantyayoś cāpitāṁś ca prācyān pracakṣate
Translation:
The five hundred disciples of Pauṣyañji and Āvantya became known as the northern singers of the Sāma Veda, and in later times some of them also became known as eastern singers.