CC Adi-lila 04.083 - Gautamiya-tantra
Sri Caitanya-caritamrta
CC Adi-lila
CC Adi 4.83, Translation and Purport:
"The transcendental goddess Śrīmatī Rādhārāṇī is the direct counterpart of Lord Śrī Kṛṣṇa. She is the central figure for all the goddesses of fortune. She possesses all the attractiveness to attract the all-attractive Personality of Godhead. She is the primeval internal potency of the Lord."
This text is from the Bṛhad-gautamīya-tantra