Gerber, R. V. (1979). Development of competence and performance in cartographic language by children at the concrete level of map-reasoning.
Chicago-referens (17:e uppl.)Gerber, Rodney Victor. Development of Competence and Performance in Cartographic Language by Children at the Concrete Level of Map-reasoning. 1979.
MLA-referens (8:e uppl.)Gerber, Rodney Victor. Development of Competence and Performance in Cartographic Language by Children at the Concrete Level of Map-reasoning. 1979.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.