Srimad-Bhagavatam: Canto 8 - Chapter 1 - Verse 27
Sanskrit:
चतुर्थ उत्तमभ्राता मनुर्नाम्ना च तामस: ।पृथु: ख्यातिर्नर: केतुरित्याद्या दश तत्सुता: ॥ २७ ॥
ITRANS:
caturtha uttama-bhrātāmanur nāmnā ca tāmasaḥpṛthuḥ khyātir naraḥ keturity ādyā daśa tat-sutāḥ
Translation:
The brother of the third Manu, Uttama, was celebrated by the name Tāmasa, and he became the fourth Manu. Tāmasa had ten sons, headed by Pṛthu, Khyāti, Nara and Ketu.