@article{DMGAA_2001_21_2_a3,
     author = {Denecke, Klaus and Koppitz, J\"org and Wismath, Shelly},
     title = {The semantical hyperunification problem},
     journal = {Discussiones Mathematicae. General Algebra and Applications},
     pages = {175--200},
     publisher = {mathdoc},
     volume = {21},
     number = {2},
     year = {2001},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/DMGAA_2001_21_2_a3/}
}