@article{TAC_2005_14_a3,
     author = {Philip J. Higgins},
     title = {Thin elements and commutative shells  in cubical omega-categories},
     journal = {Theory and applications of categories},
     pages = {60--74},
     publisher = {mathdoc},
     volume = {14},
     year = {2005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/TAC_2005_14_a3/}
}