@article{10_21136_CMJ_1984_101989,
     author = {Cherubini, Alessandra and Varisco, Ada},
     title = {Semigroups whose proper subsemigroups are duo},
     journal = {Czechoslovak Mathematical Journal},
     pages = {630--644},
     publisher = {mathdoc},
     volume = {34},
     number = {4},
     year = {1984},
     doi = {10.21136/CMJ.1984.101989},
     mrnumber = {764445},
     zbl = {0566.20045},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.21136/CMJ.1984.101989/}
}