Reference for Numbers 4:42

וּפְקוּדֵ֕י מִשְׁפְּחֹ֖ת בְּנֵ֣י מְרָרִ֑י לְמִשְׁפְּחֹתָ֖ם לְבֵ֥ית אֲבֹתָֽם׃

And those that were numbered of the families of the sons of Merari, by their families, by their fathers’houses,

BDB