Numbers 4:41

4:41 These were those numbered from the families of the Gershonites, everyone who served in the tent of meeting, whom Moses and Aaron numbered according to the word of the Lord.

Numbers 26:57

26:57 And these are the Levites who were numbered according to their families: from Gershon, the family of the Gershonites; of Kohath, the family of the Kohathites; from Merari, the family of the Merarites.