These are the sons of Zilpah: these points back to the names in verses 16-18. Since Serah is a female, it is best to use a word like “descendants” or “offspring” that includes both sexes. See Good News Translation.

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .