text: The variable molecular descriptors based on distance related matrices.
  Recently variable molecular connectivity index and variable paths have been tested as molecular descriptors in several structure-property regressions. Here we outline the construction of several variable molecular descriptors, derived from the distance matrix and the "reversed" distance matrix. This includes the variable Balaban J index and the "reversed" Balaban index 1/J as well as a novel index 1/JJ derived from J and 1/J. All the variable descriptors mentioned were constructed by augmenting the distance matrix by replacing the diagonal zeroes with the variables x, y, z,.