Bo Li Roberto Battiti Analysis of the IEEE 802.11 DCF with Service Differentiation Support in Non-saturation Conditions. 64-73 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3266&spage=64 2004 conf/qofis/2004 QofIS db/conf/qofis/qofis2004.html#LiB04