1. NP-completeness of the hamiltonian cycle problem for bipartite graphs;Akiyama;J. Information Processing,1980
2. The edge hamiltonian path problem is NP- complete;Bertossi;Information Processing Letters,1981
3. On covering the points of a graph with point disjoint paths;Boesch,1973
4. R.S. Chang, Optimal path covering for series parallel graphs, manuscript.
5. Dominating cycles in series—parallel graphs;Colbourn;Ars Combinatorica,1985