Surya Siddhanta
मेरोर् उभयतो मध्ये ध्रुवतारे नभः स्थिते । निरक्षदेशसम्स्थानाम् उभये क्षितिजाश्रये॥
The polar stars (dhruvatärä) are located between both the poles. Because of their placements in a place with no latitude (niraksha), both are fixed on the horizontal line (kshitija rekhä).
english translation