@article{SF_1975__10_134123,
     author = {J. van Leeuwen},
     title = {On the fixpoints of monogenic functions in free monoids.},
     journal = {Semigroup forum},
     pages = {315--328},
     publisher = {mathdoc},
     volume = {10},
     year = {1975},
     zbl = {0299.20044},
     url = {http://geodesic.mathdoc.fr/item/SF_1975__10_134123/}
}