CC Antya 4.223
kṛṣṇa-bhakti-rasera yāhāṅ pāiye vistāra
rūpa-gosāñi — Śrīla Rūpa Gosvāmī; kailā — compiled; rasāmṛta-sindhu — the book known as Bhakti-rasāmṛta-sindhu; sāra — the essence of knowledge in devotional service; kṛṣṇa-bhakti-rasera — of the transcendental mellows in devotional service; yāhāṅ — wherein; pāiye — we can get; vistāra — elaboration.
Śrīla Rūpa Gosvāmī also wrote many books, the most famous of which is the Bhakti-rasāmṛta-sindhu. From that book one can understand the essence of devotional service to Kṛṣṇa and the transcendental mellows one can derive from such service.