Lewis, J. P. (1959). Business conditions analysis. New York: McGraw-Hill.
Trích dẫn kiểu ChicagoLewis, John P. Business Conditions Analysis. New York: McGraw-Hill, 1959.
Deismireacht MLALewis, John P. Business Conditions Analysis. New York: McGraw-Hill, 1959.
Rabhadh: D'fhéadfadh nach mbeadh na deismireachtaí seo 100% cruinn i gcónaí.