Brihat Parashara Hora Shastra
सप्तमे चाऽष्टमे शुद्धे शुभग्रहयुतेऽथवा । केन्द्रेषु शुभयुक्तेषु योगः पर्वतसंज्ञकः ॥ ७॥
Parvat Yog. Benefics in Kendras will produce Parvat Yog, as Yuvati and Randhr Bhava are vacant, or are occupied by only benefics.
english translation
saptame cA'STame zuddhe zubhagrahayute'thavA । kendreSu zubhayukteSu yogaH parvatasaMjJakaH ॥ 7॥
hk transliteration by Sanscript