@book{13351, author = {Kirkwood, Betty R. and Sterne, Jonathan A. C. and ebrary, Inc.}, title = {Essential medical statistics}, publisher = {Blackwell Pub.,}, year = {2003.}, address = {Malden, Mass. :}, edition = {2nd ed.}, url = {http://ezproxy.cc.andrews.edu/login?URL=http://site.ebrary.com/lib/andrews/Doc?id=10419207} }