1. Acknowledging more biodiversity without more species
2. Species in concept and practice: Herpetological applications;Frost D. R.;Herpetologica,1990
3. The detection and naming of geographic variation within species;Hillis D. M.;Herpetol. Rev.,2020
4. Der Gegegensatz zwischen geographischer und nichtgeographischer Variation;Jordan K.;Z. Wiss. Zool.,1905
5. What is a species?;Poulton E. B.;Proc. Entomol. Soc. Lond.,1904