Christian Laforest Arthur L. Liestman David Peleg Thomas C. Shermer Dominique Sotteau Edge-disjoint spanners of complete graphs and complete digraphs. 133-159 1999 203 Discrete Mathematics 1-3 http://dx.doi.org/10.1016/S0012-365X(99)00012-6 db/journals/dm/dm203.html#LaforestLPSS99