1. Strongly Q-differentiable functions;Boros;Real Anal. Exch.,2001
2. Approximately convex functions;Boros;Ann. Univ. Sci. Bp.,2013
3. Q-subdifferential of Jensen-convex functions;Boros;J. Math. Anal. Appl.,2006
4. On I-differentiation;Broszka;Tatra Mt. Math. Publ.,2007
5. Functions whose differences belong to a given class;de Bruijn;Nieuw Arch. Wiskd.,1951