Phaladeepika
केन्द्रे ग्रहाणामुदितं बलं यत्सुखे भवस्यस्तगृहे विलग्ने । उपर्युपर्युक्तपदक्रमेण बलाभिवृद्धि हि विकल्पयन्ति ॥ ८॥
The strength of the planets occupying he 4 Kendras (1 st, 4 th, 7 th and 10 th) has been distinguished by the astrologers in the following manner; It is 1/4 th in the 4 th house ;1/2 in the 10 th 2/3 in the 7 th and full in the 1 st or Lagna, thus increasing it by 1/4 in each stage.
english translation
kendre grahANAmuditaM balaM yatsukhe bhavasyastagRhe vilagne । uparyuparyuktapadakrameNa balAbhivRddhi hi vikalpayanti ॥ 8॥
hk transliteration by Sanscript