[1] Cosgrove, M., Fountain, C., Wehry, S., Wood, J. & Kasten, K. (2006). Randomized Field Trial of an Early Literacy Curriculum and Instructional Support System. San Francisco, CA. annual meeting of the American Educational Research Association [American Educational Research Association]. https://pdf4pro.com/cdn/randomized-field-trial-of-an-early-literacy-cur…
[2] Preschool Curriculum Evaluation Research Consortium. (2008). Effects of Preschool Curriculum Programs on School Readiness: Report from the Preschool Curriculum Evaluation Research initiative. Washington, D.C. U.S. Department of Education. https://ies.ed.gov/ncer/pubs/20082009/pdf/20082009_rev.pdf