Roberts, J. E., Chapman, R. S., & Warren, S. F. (2008). Speech & language development & intervention in Down syndrome & fragile X syndrome. Paul H. Brookes Pub.
Chicago-viite (17. p.)Roberts, Joanne E., Robin S. Chapman, ja Steven F. Warren. Speech & Language Development & Intervention in Down Syndrome & Fragile X Syndrome. Baltimore: Paul H. Brookes Pub, 2008.
MLA-viite (9. p.)Roberts, Joanne E., et al. Speech & Language Development & Intervention in Down Syndrome & Fragile X Syndrome. Paul H. Brookes Pub, 2008.
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