Schölkopf, B., Knirsch, P., Smola, A., & Burges, C. (1998). Fast approximation
of support vector kernel expansions, and an interpretation of clustering as approximation in feature spaces. In R. Levi, M.
Schanz, R.-J. Ahlers, & F. May (Eds.), Mustererkennung
1998: 20. DAGM-Symposium Stuttgart, 29. September – 1. Oktober 1998 (pp. 125-132). Berlin, Germany: Springer.