APA Style

Gay, G., Hembrooke, H. (2004.). Activity-centered design :an ecological approach to designing smart tools and usable systems . Cambridge, Mass. :: MIT Press,.

MLA Style

Gay, Geri.., Hembrooke, Helene.. "Activity-centered design :an ecological approach to designing smart tools and usable systems ". Cambridge, Mass. :: MIT Press,, 2004.. Text.