Brihat Samhita
उत्तरमार्गो याम्यऽदि निगदितो मध्यमस्तु भाग्यऽद्यः । दक्षिणमार्गोआषाढाआदि कैश्चिदेवं कृता मार्गाः ॥ ९-०६ ॥
According to others the nine constellations from Bharaṇi form the northern Vīthi or path, the nine from Pūrvaphālguni form the central path and the nine from Pūrvāṣādha form the southern path.
english translation
uttaramArgo yAmya'di nigadito madhyamastu bhAgya'dyaH । dakSiNamArgoASADhAAdi kaizcidevaM kRtA mArgAH ॥ 9-06 ॥
hk transliteration by Sanscript