@article{10_1017_S0017089500032195,
     author = {Campbell, C. M. and Miyamoto, I. and Robertson, E. F. and Williams, P. D.},
     title = {The efficiency of {PSL(2,} p)3 and other direct products of groups},
     journal = {Glasgow mathematical journal},
     pages = {259--268},
     year = {1997},
     volume = {39},
     number = {3},
     doi = {10.1017/S0017089500032195},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500032195/}
}