1. Nonlinear singular problems with indefinite potential termNikolaos Papageorgiou, Vicenţiu Rǎdulescu, Dušan Repovš, 2019, original scientific article Keywords: nonhomogeneous differential operator, indefinite potential, singular term, concave and convex nonlinearities, truncation, comparison principles, nonlinear regularity, nonlinear maximum principle Full text (file, 366,33 KB) 
2. Nonlinear, nonhomogeneous Robin problems with indefinite potential and general reactionNikolaos Papageorgiou, Vicenţiu Rǎdulescu, Dušan Repovš, 2020, original scientific article Keywords: nonhomogeneous differential operator, nonlinear regularity theory, constant sign and nodal solutions, infinitely many nodal solutions, critical groups Full text (file, 397,82 KB) 
3. Existence and multiplicity of solutions for doublephase Robin problemsNikolaos Papageorgiou, Vicenţiu Rǎdulescu, Dušan Repovš, 2020, original scientific article Keywords: double phase Robin problem, Carathéodory nonlinearity, existence theorem, superlinear case, positive solutions, resonant case Full text (file, 327,04 KB) 

5. Anisotropic singular Neumann equations with unbalanced growthNikolaos Papageorgiou, Vicenţiu Rǎdulescu, Dušan Repovš, 2022, original scientific article Keywords: modular function, truncation, comparison principle, minimal solution, anisotropic regularity Full text (file, 3,45 MB) 
6. Anisotropic (p, q)equations with gradient dependent reactionNikolaos Papageorgiou, Vicenţiu Rǎdulescu, Dušan Repovš, 2021, original scientific article Keywords: anisotropic (p, q)Laplacian, convection, nonvariational problem, nonlinear regularity theory, maximum principle, fixed point, minimal positive solution Full text (file, 392,49 KB) This document has more files! More... 
7. Positive solutions for nonlinear Neumann problems with singular terms and convectionNikolaos Papageorgiou, Vicenţiu Rǎdulescu, Dušan Repovš, 2020, original scientific article Keywords: singular term, convection term, nonlinear regularity, nonlinear maximum principle, LeraySchauder alternative theorem, fixed point theory Full text (file, 337,30 KB) 
8. Ground state and nodal solutions for a class of double phase problemsNikolaos Papageorgiou, Vicenţiu Rǎdulescu, Dušan Repovš, 2020, original scientific article Keywords: double phase operator, weight function, superlinear reaction, Nehari manifold, ground state solution, nodal solution Full text (file, 349,88 KB) 

10. Nonlinear nonhomogeneous singular problemsNikolaos Papageorgiou, Vicenţiu Rǎdulescu, Dušan Repovš, 2020, original scientific article Keywords: singular term, superlinear perturbation, positive solution, nonhomogeneous differential operator, nonlinear regularity, minimal positive solutions, strong comparison principle Full text (file, 416,38 KB) 