Ramayana
सततं राजवृत्ते हि ज्येष्ठो राज्येऽभिषिच्यते । राज्ञामेतत्समं तत्स्यादिक्ष्वाकूणां विशेषतः ॥ २-७३-२२
According to the established law of royalty, the eldest son is invariably crowned in the kingdom. This is true of all kings. This is a special tradition of the kings of the Ikshvaku race. ॥ 2-73-22॥
english translation
satataM rAjavRtte hi jyeSTho rAjye'bhiSicyate । rAjJAmetatsamaM tatsyAdikSvAkUNAM vizeSataH ॥ 2-73-22
hk transliteration by Sanscript