Genetic fixity in the human major histocompatibility complex and block size diversity in the class I region including HLA-E. - Romero V; Larsen CE; Duke-Cohan JS; Fox EA; Romero T; Clavijo OP; Fici DA; Husain Z; Almeciga I; Alford DR; Awdeh ZL; Zuñiga J; et al. (BMC genetics, 2007)