Petermann, T.De Los Rios, P.2010-03-222010-03-222010-03-22200410.1016/j.jtbi.2004.02.017https://infoscience.epfl.ch/handle/20.500.14299/48357WOS:000222192000001Cluster approximations for epidemic processes: a systematic description of correlations beyond the pair leveltext::journal::journal article::research article