Brihat Parashara Hora Shastra
ततः क्रमेणौजराशौ समे नेया तथोऽत्क्रमात् । त्रिकूटानां च विज्ञेयाः स्थिरवच्च दशा समाः ॥ १८०॥
If the Rāśi of commencement is an odd Rāśi, the Dashas of 3 Movable, 3 Fixed and 3 Dual Rāśis will be counted in the onwards order. They will be in the reverse order in the case of an even Rāśi. In this system the Dasha years will be the same, as in Sthir Dasha. In this system every Dasha is of the next 3rd Rāśi.
english translation
tataH krameNaujarAzau same neyA tatho'tkramAt । trikUTAnAM ca vijJeyAH sthiravacca dazA samAH ॥ 180॥
hk transliteration by Sanscript