Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 11
Sanskrit:
सोऽसृजत्तपसा युक्तो रजसा मदनुग्रहात् ।लोकान् सपालान् विश्वात्मा भूर्भुवः स्वरिति त्रिधा ॥ ११ ॥
ITRANS:
so ’sṛjat tapasā yuktorajasā mad-anugrahātlokān sa-pālān viśvātmābhūr bhuvaḥ svar iti tridhā
Translation:
Lord Brahmā, the soul of the universe, being endowed with the mode of passion, performed great austerities by My mercy and thus created the three planetary divisions, called Bhūr, Bhuvar and Svar, along with their presiding deities.