1. Boshier, D. O., Enlarging properties of graphs, Ph.D. Thesis, Royal Holloway and Bedford New Colledge, University of London, 1987.
2. Cheeger, J., A lower bound for the smallest eigenvalue of the Laplacian, In: Problems in Analysis, Princeton University Press, 1970, 159–199.
3. De Millo, R.A., Eisenstat, S. C., Lipton, R. J., Preserving average proximity in arrays, Communications of the ACM, 21, 1978, 228–230.
4. Diks, K., Djidjev, H. N., Sýkora, O., Vrťo, I., Edge separators for planar graphs and their applications, In: Proc. of the 13-th Symposium on Mathematical Foundations of Computer Science, LNCS 324, Springer Verlag, 1988, 280–290.
5. Diks, K., Djidjev, H. N., Sýkora, O., Vrťo, I., Edge separators for planar graphs with applications, Journal of Algorithms, to appear.