@Article{GrueKornilowicz07,
 author        = {Klaus E. Grue and Artur Korni{\l}owicz},
 year          = {2007},
 title         = {Basic Operations on Preordered Coherent Spaces},
 journal       = {Formalized Mathematics},
 volume        = {15},
 number        = {4},
 pages         = {201--229}
}