וַיִּהְי֣וּ בְנֵי־יְהוּדָה֮ לְמִשְׁפְּחֹתָם֒ לְשֵׁלָ֗ה מִשְׁפַּ֙חַת֙ הַשֵּׁ֣לָנִ֔י לְפֶ֕רֶץ מִשְׁפַּ֖חַת הַפַּרְצִ֑י לְזֶ֕רַח מִשְׁפַּ֖חַת הַזַּרְחִֽי׃
And the sons of Judah after their families were: of Shelah, the family of the Shelanites; of Perez, the family of the Perezites; of Zerah, the family of the Zerahites.
Read halakhic rulings (Jewish law) on Numbers 26:20: and classical halakhic sources.