Siegel, S. Nonparametric Methods for the Behavioral Sciences. New York: McGraw-Hill, 1956. p. 63 (when both variables are two-point scales, McNemar's test of symmetry and McNemar's test for the significance of changes are equivalent); Bowker, A. H., A test for symmetry in contingency tables. Journal of the American Statistical Association 43 (1948): 572-574.