OER Recommender: Linking NSDL Pathways and OpenCourseWare Repositories. - Joel Duffin; Brandon Muramatsu (Bull. IEEE Tech. Comm. Digit. Libr., 2009)

Linking open course wares and open education resources: creating an effective search and recommendation system. - Brett E. Shelton; Joel Duffin; Yuxuan Wang; Justin Ball (RecSysTEL@RecSys, 2010)