My Erdös number is 3:
  1. de Caen, D.; Erdos, P.; Pullmann, N. J.; Wormald, N. C. Extremal clique coverings of complementary graphs. Combinatorica 6 (1986), no. 4, 309--314.
  2. Sterling, Leon S.; Wormald, Nicholas. A remark on the construction of designs for two-way elimination of heterogeneity. Bull. Austral. Math. Soc. 14 (1976), no. 3, 383-388.
  3. Edmund Kazmierczak, Philip Dart, Leon Stirling and Michael Winikoff. Verifying Requirements Through Mathematical Modelling and Animation. International Journal of Software Engineering and Knowledge Engineering, Vol. 10, No. 2 (2000), p251-273.