Auschwitz and After by 
Concentration Camps in Nazi Germany by 
Inside the Vicious Heart by 
Legacies of Dachau by 
Nazi Mass Murder by Survivors, Victims and Perpetrators by 
Testimony from the Nazi Camps by 
The Business of Genocide by 
The Holocaust Sites of Europe by The Order of Terror by Both JSTOR and Project Muse have good, peer-reviewed articles on this topic. Here are some interesting ones to get you started.
Zweig, R. W. (1998). "Feeding the Camps: Allied Blockade Policy and the Relief of Concentration Camps in Germany, 1944-1945," The Historical Journal, 41.3, pp 825-851.
Abel, T. (1951). "The Sociology of Concentration Camps," Social Forces, 30.2, pp 150-155.
Maher, T.V. (2010). "Threat, Resistance, and Collective Action: the Cases of Sobibor, Treblinka, and Auschwitz," American Sociological Review, 75.2, pp 252-272.
Giaccaria, P. and Minca, C. (2011). "Topographies/topologies of the camp: Auschwitz as a spatial threshold." Political Geography, 30.1, pp 3-12.
The web site that has the most complete information on the Nazi camps all in one place or easily linked is the United States Holocaust Memorial Museum. Here are some other sites that may be of interest: