@article{AM2_1990__39_2-3_137333,
     author = {Jaroslav Ber\'anek and Jan Chvalina},
     title = {On {Tabor's} problem concerning a certain quasi-ordering of iterative roots of functions.},
     journal = {Aequationes mathematicae},
     pages = {1--5},
     publisher = {mathdoc},
     volume = {39},
     number = {2-3},
     year = {1990},
     zbl = {0702.26009},
     url = {http://geodesic.mathdoc.fr/item/AM2_1990__39_2-3_137333/}
}