Hughes, J. L. (1962). Programed instruction for schools and industry. Science Research Associates.
Chicago-viite (17. p.)Hughes, John Leo. Programed Instruction for Schools and Industry. Chicago: Science Research Associates, 1962.
MLA-viite (9. p.)Hughes, John Leo. Programed Instruction for Schools and Industry. Science Research Associates, 1962.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.