(1913). Inherited tendencies of secondary instruction in the United States / by Herbert Galen Lull.
Chicago-viite (17. p.)Inherited Tendencies of Secondary Instruction in the United States / by Herbert Galen Lull. 1913.
MLA-viite (9. p.)Inherited Tendencies of Secondary Instruction in the United States / by Herbert Galen Lull. 1913.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.