Computers and Intractability: A Guide to the Theory of NP-Completeness.
Some NP-complete geometric problems
Proceedings of the eighth annual ACM symposium on Theory of computing - STOC ’76
D. S. Johnson
R. L. Graham
David S. Johnson
The geometric maximum traveling salesman problem
Comparando mapas conceituais utilizando correspondência de grafos
Polynomial time approximation schemes for Euclidean traveling salesman and other geometric problems