In 2003, the ICZN ruled in its Opinion 2027 that if wild animals and their domesticated derivatives are regarded as one species, then the scientific name of that species is the scientific name of the wild animal. In 2005, the third edition of Mammal Species of the World upheld Opinion 2027 with the name Lupus and the note: "Includes the domestic dog as a subspecies, with the dingo provisionally separate - artificial variants created by domestication and selective breeding". However, Canis familiaris is sometimes used due to an ongoing nomenclature debate because wild and domestic animals are separately recognizable entities and that the ICZN allowed users a choice as to which name they could use, and a number of internationally recognized researchers prefer to use Canis familiaris.