Ralston Purina Co. and Protein Technologies International's work with soybeans and soybean products : bibliography and sourcebook 1934 to 1993 : detailed information on 293 published documents (extensively annotated bibliography), 44 commercial soy products, 42 original interviews (many full text) and overviews, 16 unpublished archival documents / compiled by William Shurtleff & Akiko Aoyagi.