@article{JIS_2010__13_8_a6,
     author = {El Bachraoui,  Mohamed and Salim,  Mohamed},
     title = {Combinatorial identities involving the {M\"obius} function},
     journal = {Journal of integer sequences},
     year = {2010},
     volume = {13},
     number = {8},
     zbl = {1252.11003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JIS_2010__13_8_a6/}
}