Online Mendelian Inheritance in Man: Costello Syndrome - References, gene map, and clinical synopsis. - http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=OMIM&dopt=Detailed&tmpl=dispomimTemplate&list_uids=218040
Costello Kids - Official site of the International Costello Syndrome Support Group. Includes medical information, photographs and videos, therapy ideas, news, and links. - http://www.costellokids.co.uk/