Helmholtz, H. v., Bryan, C. L., & Davis, H. T. (1930). Counting and measuring. D. Van Nostrand Company.
Chicago Style (17th ed.) CitationHelmholtz, Hermann von, Charlotte Lowe Bryan, and Harold T. Davis. Counting and Measuring. New York: D. Van Nostrand Company, 1930.
MLA (9th ed.) CitationHelmholtz, Hermann von, et al. Counting and Measuring. D. Van Nostrand Company, 1930.
Warning: These citations may not always be 100% accurate.