@article{SF_1981__23_134516,
     author = {W.D. Burgess},
     title = {The injective hull of {S-sets,} {S} a semilattice of groups.},
     journal = {Semigroup forum},
     pages = {241--246},
     publisher = {mathdoc},
     volume = {23},
     year = {1981},
     zbl = {0479.20035},
     url = {http://geodesic.mathdoc.fr/item/SF_1981__23_134516/}
}