@article{Kominek:2009,
author
=
"Z.Kominek and J.Matkowski",
title
=
"On the existence of a convex solution of the functional equation $\varphi (x)=h(x,\,\varphi [f(x)])$",
journal
=
"Annales Polonici Mathematici",
volume
=
"Vol. 30",
pages
=
"1--4",
year
=
"1974",
}