@book{196519,
	author = {Sigman, Marian. and Ruskin, Ellen.},
	title = {Continuity and change in the social competence of children with autism, Down syndrome, and developmental delays},
	publisher = {Blackwell Publishers},
	year = {c1999.},
	series = {Monographs of the Society for Research in Child Development},
	address = {Malden, MA}
}