Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 42
Sanskrit:
तयोवान पुनरेवाहमदित्यामास कश्यपात् ।उपेन्द्र इति विख्यातो वामनत्वाच्च वामन: ॥ ४२ ॥
ITRANS:
tayor vāṁ punar evāhamadityām āsa kaśyapātupendra iti vikhyātovāmanatvāc ca vāmanaḥ
Translation:
In the next millennium, I again appeared from the two of you, who appeared as My mother, Aditi, and My father, Kaśyapa. I was known as Upendra, and because of being a dwarf, I was also known as Vāmana.