Prajāpati-vaṃśānukīrtana — Genealogical Enumeration of Progenitors
Dharma’s Line and the Sādhyas
तिस्रस्तु विथयो ह्येता उत्तरो मार्ग उच्यते / पूर्वोत्तरे च फल्गुन्यौ मघा चैवार्षभी स्मृता
tisrastu vithayo hyetā uttaro mārga ucyate / pūrvottare ca phalgunyau maghā caivārṣabhī smṛtā
These three vīthīs are called the Uttaro Mārga, the northern path. And in the northeast (pūrvottara), the two Phalgunīs and Maghā are remembered as the Ārṣabhī (vīthī).