Numbers 3:25-26

Gershon : the clan of Gershom/Gershon of the tribe of Levi

Numbers 4:24-28

Aaron : a son of Amram; brother of Moses,son of Amram (Kohath Levi); patriarch of Israel's priests,the clan or priestly line founded by Aaron

Gershonites : the clan of Gershom/Gershon of the tribe of Levi

Ithamar : son of Aaron