Special Collections (Deering Library 3rd floor) owns a non-circulating collection of many of the Hans Christian Andersen award winners (from the International Board on Books for Young People featuring authors from around the world). Search NUsearch for the phrase "Hans Christian Andersen Award" for a list of the titles Northwestern owns.
Northwestern library contains a collection of children's picture books that you may check out in the Curriculum Collection, main library, 5th floor north tower. To find the call number for a book use NUsearch. You may search by author, title or subject using Advanced Search. The subject tags for children's book are either juvenile literature or juvenile fiction.
This search will retrieve books about immigrants or immigration, taking advantage of the "wildcard" symbol *