http://www.ncbi.nlm.nih.gov/pubmed/6927693
http://www.csdsa.org/arttsl.asp
http://www.apraxia-kids.org/site/apps/nl/content3.asp?c=chKMI0PIIsE&b=788447&ct=464165
http://www.nas.org.uk/nas/jsp/polopoly.jsp?a=2186&d=364
http://autism-treatments.org/treatment-types/sign-language-for-autism/
http://sitemaker.umich.edu/356.kobza/sign_language
http://www.babies-and-sign-language.com/special-needs.html