1. Tchebycheff Systems, with Applications in Analysis and Statistics;Karlin,1966
2. Equioscillation under nonuniqueness in the approximation of continuous functions;Jones;J. Approximation Theory,1970
3. Remarks on Haar systems;Hadeler;J. Approximation Theory,1973
4. About the extension of the domain of definition of the Chebyshev systems defined on intervals of the real axis;Németh;Mathematica,1966