@article{CRMATH_2005__340_1_9_0,
     author = {Masoud Khalkhali and Bahram Rangipour},
     title = {Cup products in {Hopf-cyclic} cohomology},
     journal = {Comptes Rendus. Math\'ematique},
     pages = {9--14},
     publisher = {Elsevier},
     volume = {340},
     number = {1},
     year = {2005},
     doi = {10.1016/j.crma.2004.10.025},
     language = {en},
}