Psychologists' interest in children's art was reflected in works by Georg Kerschensteiner (Die Entwickelung der Zeichnerischen Begabung, 1905, on the grounds of analysis of some 100 000 drawings), Georges-Henri Luquet ("Les Dessins D’un Enfant", 1912, using 1500 drawings of the author's daughter from 3 to 8 years old), Georges Rouma ("Le Langage Graphique de l’Enfant", Paris, 1913), Karl Bühler (1918 ff.), Florence Goodenough, Helga Eng, Robert Coles. According to D.D. Kelly, consequent domination of Piagetian theory of cognitive psychology largely marginalized the psychological studies of children's art, which were revitalized only towards the end of the 20th century.