Lester W. Sontag, Charles T. Baker, Virginia L. Nelson
Child Development Publications1958Monographs of the Society for Research in Child Development
v. 23 ; no. 2 ; serial no. 68 ; 1958 , Fels monograph series
Child Development Publications1951Monographs of the Society for Research in Child Development
v. 15 [i.e. 14], no. 2 = serial no. 50, 1950 , Fels monograph series
no. 1