In the context of the input sentence, determine the relationship between 'American Girl' and 'doll'.
Options: owned by, employer, product/material produced, distribution format

The new boutiques will also include a selection of popular doll accessories and Dress Like Your Doll ™ girl-sized clothing, plus a variety of American Girl’s best-selling books , the 2015 Girl of the Year movie , and American Girl ® magazine —all available in Spanish.
product/material produced