@BOOK{Friendly:00:VCD, title = {Visualizing Categorical Data}, publisher = {SAS Institute}, year = {2000}, author = {Michael Friendly}, address = {Cary, NC}, isbn = {1-58025-660-0} } @BOOK{Friendly:91, title = {{SAS System} for Statistical Graphics}, publisher = {SAS Institute}, year = {1991}, author = {Michael Friendly}, address = {Cary, NC}, edition = {1st}, isbn = {1-55544-441-5}, }