Brihat Parashara Hora Shastra
तनुभावपदं विप्र प्रधानं पदमुच्यते । तनोरनुचराद्यत् स्यादुपारूढं तदुच्यते ॥ २॥
Upa Pad is calculated for the Bhava, following the natal Lagn. This Upa Pad is also called Gaun Pad.
english translation
tanubhAvapadaM vipra pradhAnaM padamucyate । tanoranucarAdyat syAdupArUDhaM taducyate ॥ 2॥
hk transliteration by Sanscript