Topical Studies for Numbers 3:20:
House {Forerunner Commentary}
House {Nave's Topical Bible}
Levites {Forerunner Commentary}
Levites {Nave's Topical Bible}
Mahli {Nave's Topical Bible}
Merari {Nave's Topical Bible}
Mushi {Nave's Topical Bible}
Families {Torrey's Topical Textbook}