On orthonormal product systems. Schipp, Ferenc — 2004 Acta Mathematica Academiae Paedagogicae Nyí regyháziensis. New Series [electronic only]
Discrete Laguerre functions and equilibrium conditions. Schipp, Ferenc — 2001 Acta Mathematica Academiae Paedagogicae Nyí regyháziensis. New Series [electronic only]
Discrete orthogonality of Zernike functions. Pap, Margit; Schipp, Ferenc — 2005 Mathematica Pannonica