[Note: I originally picked this up thinking that it would cover literary female cross-dressing knights as well as male ones. Although the article is entirely about men cross-dressing as women, it helps to round out the picture of how medieval people viewed clothing as a gender signifier and some of the asymmetries of cross-gender behavior.]
Putter looks at the phenomenon of (male) cross-dressing knights, both in historical records and in chivalric romances and considers how the topic contributes to our understanding of gender and sex categories in the middle ages.