Phaladeepika
लग्नेन्द्वोस्तदधीसयोरपि मिथो लग्नेशरन्ध्रेशयो- र्द्रेक्काणास्वनवांशकादपि मिथस्तद्द्वादशांशात्क्रमात् । आयुर्दीर्घसमाल्पतां चरनगव्द्यांगैश्चरेऽथ स्थिरे ब्रूयाद्द्वन्द्वचरस्थिरैरुभयभैः स्थास्नुद्विदेहाटनैः ॥ १४॥
One should determine the longevity—whether long, medium, or short—based on the relationship between the ascendant (lagna) and the Moon, the lords of those two signs, the lord of the ascendant and the lord of the eighth house, and likewise from the signs of the dṛkkāṇa, the navāṃśaka, and the dvādaśāṃśa, respectively. The determination is made according to whether these pairs reside in movable (cara), fixed (sthira), or dual (dvyaṅga) signs: if they are in a movable and a movable sign, a fixed and a dual sign, or a dual and a fixed sign, they indicate long life; whereas other combinations of movable, fixed, and dual signs indicate medium or short life.
english translation
lagnendvostadadhIsayorapi mitho lagnezarandhrezayo- rdrekkANAsvanavAMzakAdapi mithastaddvAdazAMzAtkramAt । AyurdIrghasamAlpatAM caranagavdyAMgaizcare'tha sthire brUyAddvandvacarasthirairubhayabhaiH sthAsnudvidehATanaiH ॥ 14॥
hk transliteration by Sanscript