Marek Hajduczenia Pedro R. M. Inácio Henrique J. A. da Silva Mário M. Freire Paulo P. Monteiro 68-83 2007 9 IEEE Communications Surveys and Tutorials 1-4 http://dl.comsoc.org/cocoon/comsoc/servlets/OntologySearch?query=&node=TOC1775&render=false&type=1 db/journals/comsur/comsur9.html#HajduczeniaISFM07