  The concept of asymmetric copulas is revisited and is made more precise. We
give a rigorous topological argument for opportunity to define asymmetry
measures defined recently by K.F Siburg [6] through exhibiting at least three
ordered classes of copulas according to a suitable equivalence relation. We
define a process of ordering subcopulas which makes clearer the degree of
asymmetry. As illustration, we treat the asymmetric Cobb-Douglas utility model.
