@article{10_4064_cm114_2_7,
     author = {Petter Andreas Bergh},
     title = {Orbit algebras and periodicity},
     journal = {Colloquium Mathematicum},
     pages = {245--252},
     publisher = {mathdoc},
     volume = {114},
     number = {2},
     year = {2009},
     doi = {10.4064/cm114-2-7},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/cm114-2-7/}
}