Brihat Parashara Hora Shastra
मूलाज्जन्मर्क्षपर्यन्तं गणयेदष्टभिर्भजेत् । शेषाद्दशाधीपा ज्न्`एया अष्टौ रव्यादयः क्रमात् ॥ ३७॥
This Dasha system is considered suitable in cases, where the Lord of Lagn is in Lagn, or in Yuvati. Count from Mul to the Janm Nakshatr and divide the number by 8.
english translation
mUlAjjanmarkSaparyantaM gaNayedaSTabhirbhajet । zeSAddazAdhIpA jn`eyA aSTau ravyAdayaH kramAt ॥ 37॥
hk transliteration by Sanscript