Buckhalt, J. ., El-Sheikh, M. ., Keller, P. ., & Kelly, R. . (1969). Concurrent and longitudinal relations between children’s sleep and cognitive functioning: the moderating role of parent education. Child Development, 80(3), 875-92. https://doi.org/10.1111/j.1467-8624.2009.01303.x (Original work published 1969)