@article{MS2_1967__20_165977,
     author = {Frank Harary and Gordon W. Wilcox},
     title = {Boolean {Operations} on {Graphs.}},
     journal = {Mathematica Scandinavica},
     pages = {41--51},
     publisher = {mathdoc},
     volume = {20},
     year = {1967},
     zbl = {0152.22801},
     url = {http://geodesic.mathdoc.fr/item/MS2_1967__20_165977/}
}