22. For an appreciation of these two sonatas, see Pamela Fox, “The Stylistic Anomalies of C. P. E. Bach’s Nonconstancy,” in C. P. E. Bach Studies, ed. Stephen L. Clark (Oxford: Oxford University Press, 1988), 106–109. Charles Rosen examines the Sonata in A major in Sonata Forms (New York: W. W. Norton, rev. 1988), 178–181.