Srimad Bhagavatam Canto 09, Chapter 20, Text 06

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.
Srimad Bhagavatam Canto 09, Chapter 20, Text 04-05
Srimad Bhagavatam Canto 09, Chapter 20, Text 07