1. J. Bokowski, H. Hadwiger, J.M. Wills,1976, Eine Erweiterung der Croftonschen Formeln für konvexe Körper. Mathematika 23 (1976), 212–219.
2. G.R. Burton, 1979, Subspaces which touch a Borel subset of a convex surface. J. London Math. Soc. (to appear).
3. H. Federer, 1959, Curvature measures. Trans. Amer. Math. Soc. 93 (1959), 418–491.
4. H. Federer, 1969, Geometric measure theory. Springer-Verlag, Berlin, Heidelberg, New York 1969.
5. W.J. Firey, 1972, An integral-geometric meaning for lower order area functions of convex bodies.Mathematika 19 (1972), 205–212.