Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 17
Sanskrit:
प्रागयं वसुदेवस्य क्वचिज्जातस्तवात्मज: । वासुदेव इति श्रीमानभिज्ञा: सम्प्रचक्षते ॥ १७ ॥
ITRANS:
prāgayaṁ vasudevasyakvacij jātas tavātmajaḥvāsudeva iti śrīmānabhijñāḥ sampracakṣate
Translation:
For many reasons, this beautiful son of yours sometimes appeared previously as the son of Vasudeva. Therefore, those who are learned sometimes call this child Vāsudeva.