@incollection{iiasa4749,
       booktitle = {Wissenschaft als Kultur},
          editor = {F. Stadler},
           title = {The natural history of mutual aid},
         address = {Heidelberg},
       publisher = {Springer-Verlag},
            year = {1996},
             url = {https://pure.iiasa.ac.at/id/eprint/4749/},
            isbn = {3-211-82936-9},
          author = {Sigmund, K. and Nowak, M. A.}
}