Brihat Parashara Hora Shastra
एकभे नवभे भागा भुक्ता भोग्या द्विसंगुणाः । द्विभेंऽशार्धोनिताः षष्टिरष्टभे खाग्नियुग् लवाः ॥ १०॥
If the sum is above nine Rāśis, the degrees to elapse be doubled to get the Drishti value. If the sum is above 2 Rāśis, the degrees etc. be halved and deducted from 60. If the sum exceeds 8 Rāśis, add to the degrees etc. a figure of 30 to get the Drishti value. In other cases, the sums be processed, as explained earlier.
english translation
ekabhe navabhe bhAgA bhuktA bhogyA dvisaMguNAH । dvibheM'zArdhonitAH SaSTiraSTabhe khAgniyug lavAH ॥ 10॥
hk transliteration by Sanscript