@article{CM_1972__25_3_329_0,
     author = {de Ruiter, Jan},
     title = {An improvement of a result of {I.} {N.} {Stewart}},
     journal = {Compositio Mathematica},
     pages = {329--333},
     publisher = {Wolters-Noordhoff Publishing},
     volume = {25},
     number = {3},
     year = {1972},
     mrnumber = {318252},
     zbl = {0248.17008},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1972__25_3_329_0/}
}