1. G. Krech, Approximation Theorems for Positive Linear Operators Associated with Hermite and Laguerre Polynomials. In: S. Mohiuddine, T. Acar (eds) Advances in Summability and Approximation Theory. Springer, Singapore 2018, 141-155.

  2. E. Wachnicki, G. Krech, Approximation of functions by nonlinear singular integral operators depending on two parameters, Publ. Math. Debrecen 92(3-4) (2018), 481-494.

  3. G. Krech, On the degree of approximation by modified Gamma operators, Miskolc Math. Notes 18(2) (2017), 917-923.

  4. G. Krech, A note on some positive linear operators associated with the Hermite polynomials, Carpathian J. Math. 32 (2016), 71-77.

  5. G. Krech, Some approximation results for operators of Szasz-Mirakjan-Durrmeyer type, Math. Slovaca 66 (2016), 945-958.

  6. G. Krech, R. Malejki, On the bivariate Baskakov-Durrmeyer type operators, Czasopismo Techniczne, Nauki podstawowe 16(1) (2016), 85-96.

  7. G. Krech, Modified Gamma operators in L^p spaces, Lith. Math. J. 54(4) (2014), 454-462.

  8. G. Krech, On the rate of convergence for modified Gamma operators, Rev. Un. Mat. Argentina 55(2) (2014), 123-131.

  9. G. Krech,  On some approximation theorems for the Poisson integral for Hermite expansions, Analysis Mathematica 40 (2014), 133-145.

  10. G. Krech, E. Wachnicki, Direct estimate for some operators of Durrmeyer type in exponential weighted space, Demonstratio Mathematica 47(2) (2014), 336-349.

  11. G. Krech, Boundary value problems for Poisson integrals for Hermite expansions, Scientific Issues Jan Długosz University in Częstochowa, Mathematics 19 (2014), 185-189.

  12. G. Krech, An investigation of the approximation of functions of two variables by the Poisson integral for Hermite expansions, Czasopismo Techniczne, Nauki Podstawowe 3 (2014), 31-38.

  13. G. Krech, A note on the paper "Voronovskaya type asymptotic approximation by modified Gamma operators", Applied Mathematics and Computation 219 (2013), 5787-5791.

  14. G. Krech, The Voronovskaya type theorem for Poisson integrals of functions of two variables, Commentationes Mathematicae 53.1 (2013), 23-34.

  15. G. Krech, E. Wachnicki, Approximation by some combinations of Poisson integrals for Hermite and Laguerre expansions, Ann. Univ. Paedagog. Crac. Stud. Math. 12 (2013), 21-29.

  16. G. Krech, The Poisson integrals of functions of two variables for Hermite and Laguerre expansions, Prace Naukowe Akademii im. Jana Długosza w Częstochowie, Matematyka 16 (2011), 47-54.

  17. G. Krech, I. Krech, On some nontransitive relation, Proceedings of International Conference Presentation of Mathematics '09, Technical University of Liberc 2010, 53-58.

  18. G. Krech, On the convergence theorem for alternate Poisson integral of function of two variables for Laguerre expansions, Mathematica, Scientific Issues / Catholic University in Ruzomberok 2 (2009), 15-22.

  19. G. Krech, On the alternate Poisson integral of function of two variables for Hermite expansions, South Bohemia Mathematical Letters 17.1 (2009), 33-38.

  20. G. Krech, On the rate of convergence theorem for the alternate Poisson integrals for Hermite and Laguerre expansions, Annales Academiae Paedagogicae Cracoviensis, Studia Mathematica 4 (2004), 103-110.

  21. G. Toczek, E. Wachnicki, On the rate of convergence and the Voronovskaya theorem for the Poisson integrals for Hermite and Laguerre expansions, Journal of Approximation Theory 116 (2002), 113-125.

  22. G. Toczek, O przygotowaniu nauczyciela matematyki do wyboru podręcznika, Zeszyty Naukowe Uniwersytetu Rzeszowskiego, Seria Matematyczno-Przyrodnicza, Matematyka 1 (2001), 244-254.