A set of novel vertex-degree-based invariants was introduced by Gutman, denoted by SO₁, SO₂, . . . , SO₆. These invariants were constructed through geometric reasoning based on a new graph invariant ...
Citations: Vohra, Rakesh. 1984. Counting Spanning Trees in a Graph of Kleitman and Golden and its Generalization. Journal of the Franklin Institute. (5)349-355.