Linda Darling-Hammond, Nicole Ramos-Beban, Rebecca Padnos Altamirano, Maria E. Hyler (2016). “Be the Change: Reinventing School for Student Success”, p.114, Teachers College Press
Arnold Gesell, Frances Lillian Ilg (1951). “Infant and Child in the Culture of Today: The Guidance of Development in Home and Nursery School (From the Former Clinic of Child Development, School of Medicine at Yale University)”