@article{MSH_1997__137__37_0,
     author = {Hummell, Hans J. and Sodeur, Wolfgang},
     title = {Structural analysis of social networks with respect to different levels of aggregation},
     journal = {Math\'ematiques informatique et sciences humaines},
     pages = {37--60},
     publisher = {Ecole des hautes-\'etudes en sciences sociales},
     volume = {137},
     year = {1997},
     mrnumber = {1454785},
     zbl = {0885.92043},
     language = {en},
     url = {http://www.numdam.org/item/MSH_1997__137__37_0/}
}