@article{10_1007_s10587_013_0019_z,
     author = {Petrich, Mario},
     title = {Normal cryptogroups with an associate subgroup},
     journal = {Czechoslovak Mathematical Journal},
     pages = {289--305},
     publisher = {mathdoc},
     volume = {63},
     number = {2},
     year = {2013},
     doi = {10.1007/s10587-013-0019-z},
     mrnumber = {3073960},
     zbl = {06236413},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.1007/s10587-013-0019-z/}
}