APA (7th ed.) Citation
Osborn, R., Boyd, C. C., Houston, W. R., & DeVault, M. V. (1961). Extending mathematics understanding. Charles E. Merrill.
Chicago Style (17th ed.) Citation
Osborn, Roger, Claude C. Boyd, W. Robert Houston, and M Vere DeVault. Extending Mathematics Understanding. USA: Charles E. Merrill, 1961.
MLA (9th ed.) Citation
Osborn, Roger, et al. Extending Mathematics Understanding. Charles E. Merrill, 1961.
Warning: These citations may not always be 100% accurate.