Brihat Parashara Hora Shastra
लग्नं केन्द्रत्रिकोणत्वाद् विशेषेण शुभप्रदम् । पञ्चमं नवमं चैव विशेषधनमुच्यते ॥ ३॥
The Lord of a Kon will give auspicious results. The Lord of Lagn is specially auspicious, as Lagn is a Kendr, as well as a Kon.
english translation
lagnaM kendratrikoNatvAd vizeSeNa zubhapradam । paJcamaM navamaM caiva vizeSadhanamucyate ॥ 3॥
hk transliteration by Sanscript