Cummings, E. Mark
Cummings, E.M. (2003). Towards Assessing Attachment on an Emotional Security Continuum. Developmental Psychology, 39, 423-429.
Waters, E., & Cummings, E.M. (2000). A Secure Base from which to Explore Relationships. Child Development, 71, 164-172.
Greenberg, M.T., Cicchetti, D., & Cummings, E.M. (1990). Attachment during the preschool years: Theory, research and intervention. Chicago: University of Chicago Press.