@article{10_4153_CMB_2006_005_4,
     author = {Doeraene, Jean-Paul and Haouari, Mohammed El},
     title = {The {Ganea} and {Whitehead} {Variants} of the {Lusternik{\textendash}Schnirelmann} {Category}},
     journal = {Canadian mathematical bulletin},
     pages = {41--54},
     year = {2006},
     volume = {49},
     number = {1},
     doi = {10.4153/CMB-2006-005-4},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-2006-005-4/}
}