Brihat Parashara Hora Shastra
दशारम्भे शुभस्थाने स्थितस्यापि शुभं फलम् । अशुभस्थानगस्यैवं शुभस्यापि न शोभनम् ॥ ८॥
It is therefore essential, that the placement of a Grah at the time of birth and at the commencement of the Dasha should both be taken into account for the assessment of the Dasha effects.
english translation
dazArambhe zubhasthAne sthitasyApi zubhaM phalam । azubhasthAnagasyaivaM zubhasyApi na zobhanam ॥ 8॥
hk transliteration by Sanscript