@article{ITA_2003__37_1_1_0,
     author = {Bradfield, Julian C.},
     title = {Fixpoints, games and the difference hierarchy},
     journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications},
     pages = {1--15},
     publisher = {EDP-Sciences},
     volume = {37},
     number = {1},
     year = {2003},
     doi = {10.1051/ita:2003011},
     mrnumber = {1991748},
     zbl = {1043.03038},
     language = {en},
     url = {http://www.numdam.org/articles/10.1051/ita:2003011/}
}