Hair, J., Bush R., Ortinau J: Marketing research: within a changing information environment. Boston, Mass.: McGraw-Hill/Irwin, 2006. ISBN 00-728-3087-5.
Hair, J., Bush R., Ortinau J: Marketing research: within a changing information environment. Boston, Mass.: McGraw-Hill/Irwin, 2006. ISBN 00-728-3087-5.