Crook, W. J., & Crook, W. J. (1958). Abacus arithmetic: How to perform some calculations on the chinese abacus. Palo Alto, Calif.: Pacific Books.
Chicago Style CitationCrook, Welton J., and Welton J. Crook. Abacus Arithmetic: How to Perform Some Calculations On the Chinese Abacus. Palo Alto, Calif.: Pacific Books, 1958.
MLA CitationCrook, Welton J., and Welton J. Crook. Abacus Arithmetic: How to Perform Some Calculations On the Chinese Abacus. Palo Alto, Calif.: Pacific Books, 1958.
Warning: These citations may not always be 100% accurate.