1. Complexity of finding embeddings in a k-tree;Arnborg,1984
2. Computers and Intractability;Garey,1979
3. On the complexity of combinatorial problems;Karp;Networks,1975
4. Searching and pebbling;Kirousis,1984
5. Well-quasi-ordering, the tree theorem, and Vázsonyi's conjecture;Kruskal;Trans. Amer. Math. Soc.,1960