Blackburn, J. E., & Powell, W. C. (1976). One at a time all at once: The creative teacher's guide to individualized instruction without anarchy. Scott, Foresman.

Blackburn, Jack E., and William Conrad Powell. One at a Time All at Once: The Creative Teacher's Guide to Individualized Instruction Without Anarchy. Glenview, Ill.: Scott, Foresman, 1976.

Blackburn, Jack E., and William Conrad Powell. One at a Time All at Once: The Creative Teacher's Guide to Individualized Instruction Without Anarchy. Scott, Foresman, 1976.