@article{iiasa4326,
          volume = {1},
          number = {1},
           title = {Darwin's "circles of complexity": Assembling ecological communities},
       publisher = {Wiley-Blackwell},
         journal = {Complexity},
             doi = {10.1002/cplx.6130010109},
           pages = {40--44},
            year = {1995},
             url = {https://pure.iiasa.ac.at/id/eprint/4326/},
            issn = {1099-0526},
          author = {Sigmund, K.}
}