@article{JEMS_2012_14_1_a4,
     author = {Clemens Fuchs and Umberto Zannier},
     title = {Composite rational functions expressible with few terms},
     journal = {Journal of the European Mathematical Society},
     pages = {175--208},
     publisher = {mathdoc},
     volume = {14},
     number = {1},
     year = {2012},
     doi = {10.4171/jems/299},
     url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/299/}
}