Alan J. Hoffman, The Change in the Least Eigenvalue of the Adjacency Matrix of a Graph Under Imbedding, SIAM Journal on Applied Mathematics, Vol. 17, No. 4 (Jul., 1969), pp. 664-671 ...

In this paper, we describe three graph theoretic heuristics that attempt to determine an optimal planar adjacency graph from a REL chart. Our computational experience suggests that these methods can ...