1. The Growth of Biological Thought;Mayr,1982
2. Comments on the search for a ‘perfect system’;Stebbins;Taxon,1969
3. A hierarchy of species concepts: the denouement in the saga of the species problem;Mayden,1997
4. The general lineage concept of species and the defining properties of the species category;de Queiroz,1999
5. Keywords in Evolutionary Biology;Keller,1992