Srimad-Bhagavatam: Canto 12 - Chapter 1 - Verse 4
Sanskrit:
पुराणसंहितामेतामश्रौष्म भवतो वयम् ।यस्यां खलूत्तम:श्लोको भगवाननुवर्ण्यते ॥ ४ ॥
ITRANS:
purāṇa-saṁhitām etāmaśrauṣma bhavato vayamyasyāṁ khalūttamaḥ-ślokobhagavān anuvarṇyate
Translation:
I have heard from you this Śrīmad-Bhāgavatam, which is the perfect summary of all the Purāṇas and which perfectly describes the Supreme Lord, Uttamaḥśloka.