On certain organic compounds with one mono-substitution and at least   three di-substitution homogeneous derivatives
  In this paper parent substances with molecules which can be divided into a skeleton and six univalent substituents, and that have the properties mentioned in the title, are considered. Two instances are the molecules of benzene and cyclopropane. The Lunn-Senior's symmetry groups of substitution isomerism of these compounds are described and upper bounds of the numbers of their di-substitution and tri-substitution homogeneous derivatives are found. Lists of the possible simple substitution reactions among di-substitution homogeneous derivatives, on one hand, and di-substitution heterogeneous, and tri-substitution homogeneous derivatives, on the other, are given. These substitution reactions allow for some derivatives to be identified with their structural formulae. 
Valentin Vankov Iliev