@article{SF_1977__14_186382,
     author = {F.W. Roush and K.H. Kim},
     title = {On generating regular elements in the semigroup of binary relations.},
     journal = {Semigroup forum},
     pages = {29--32},
     publisher = {mathdoc},
     volume = {14},
     year = {1977},
     zbl = {0356.20055},
     url = {http://geodesic.mathdoc.fr/item/SF_1977__14_186382/}
}