Marks of permutation groups and isomer enumeration

The concept of the mark of a permutation group is at least eighty years old, but comparatively little use has been made of it until recently. Redfield rediscovered marks in the 1930's, but his work was not published until 1984. He used them to count group reduced distributions according to their symmetry groups. In this paper, the Mark Version of Redfield's Superposition Theorem is used to count isomers. The method is compared with a related method used by Hässelbarth, Mead and Fujita.