1. A moment problem in L1 approximation;Hobby,1965
2. Topological Methods in the Theory of Nonlinear Integral Equations;Krasnosel'ski,1964
3. A. A. Melkman and C. A. Micchelli, “On Nonuniqueness of Optimal Subspaces for L2 n-width,” to appear Illinois Journal of Mathematics.
4. On n-widths in L∞;Micchelli;Trans. Amer. Math. Soc.,1977