Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 24
Sanskrit:
तस्मात् समरथस्तस्य सुत: सत्यरथस्तत: ।आसीदुपगुरुस्तस्मादुपगुप्तोऽग्निसम्भव: ॥ २४ ॥
ITRANS:
tasmāt samarathas tasyasutaḥ satyarathas tataḥāsīd upagurus tasmādupagupto ’gni-sambhavaḥ
Translation:
The son of Kṣemādhi was Samaratha, and his son was Satyaratha. The son of Satyaratha was Upaguru, and the son of Upaguru was Upagupta, a partial expansion of the fire-god.