@article{SF_1984__29_134694,
     author = {S. Bulman-Fleming and K. McDowell},
     title = {Flatness and amalgamation in semigroups.},
     journal = {Semigroup forum},
     pages = {337--342},
     publisher = {mathdoc},
     volume = {29},
     year = {1984},
     zbl = {0542.20041},
     url = {http://geodesic.mathdoc.fr/item/SF_1984__29_134694/}
}