SB 9.20.6
rteyo rantinavo ’bhut
trayas tasyatmaja nrpa
sumatir dhruvo ’pratirathah
kanvo ’pratirathatmajah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Rteyu had a son named Rantinava, who had three sons, named Sumati, Dhruva and Apratiratha. Apratiratha had only one son, whose name was Kanva.