@article{10_4153_CJM_1990_030_8,
     author = {Berend, Daniel},
     title = {IP-Sets on the {Circle}},
     journal = {Canadian journal of mathematics},
     pages = {575--589},
     year = {1990},
     volume = {42},
     number = {4},
     doi = {10.4153/CJM-1990-030-8},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1990-030-8/}
}