@article{AM2_1972__8_136296,
     author = {J.D. Becker and E.T. Ordman},
     title = {On {Functions} {Defined} by {Iterations} of {Each} {Other.}},
     journal = {Aequationes mathematicae},
     pages = {238--241},
     publisher = {mathdoc},
     volume = {8},
     year = {1972},
     zbl = {0257.39002},
     url = {http://geodesic.mathdoc.fr/item/AM2_1972__8_136296/}
}