@article{AM2_1976__14_136617,
     author = {K.D. Jr. Magill and S. Subbiah},
     title = {The partially ordered collection of regular ...-classes of {S(X).} {(Short} {Communication).}},
     journal = {Aequationes mathematicae},
     pages = {509--509},
     publisher = {mathdoc},
     volume = {14},
     year = {1976},
     url = {http://geodesic.mathdoc.fr/item/AM2_1976__14_136617/}
}