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.
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: