1. Knots and links in spatial graphs
2. Formal Knot Theory, Mathematical Notes, 30, Princeton University Press, Princeton, NJ, 1983.
3. and ?Some remarks on knots and links in spatial graphs?, in Knots 90, Osaka, 1990; de Gruyter, Berlin, 1992, pp. 435-445.
4. and Constructive results from graph minors: linkless embeddings, 29th Annual Symposium on Foundations of Computer Science, IEEE, 1988, pp. 398-409.