1. Interpolation by ridge functions;Braess;J. Approx. Theory,1993
2. When is f(x,y)=u(x)+v(y) ?;Cowsik;Proc. Indian Acad. Sci. Math. Sci.,1999
3. A superposition theorem for bounded continuous functions;Demko;Proc. Amer. Math. Soc.,1977
4. A superposition theorem for unbounded continuous functions;Doss;Trans. Amer. Math. Soc.,1977
5. An improvement in the smoothness of the functions in A. N. Kolmogorov’s theorem on superpositions;Fridman;Dokl. Akad. Nauk SSSR,1967