@article{RCM_2007_41_Especial_a8,
     author = {Enrique Casanovas Universidad de Barcelona and Espa\~na},
     title = {Simplicity simplified},
     journal = {Revista colombiana de matematicas},
     pages = {263--277},
     year = {2007},
     volume = {41},
     number = {Especial},
     url = {http://geodesic.mathdoc.fr/item/RCM_2007_41_Especial_a8/}
}