Παραπομπή APA
Heelis, F. 1. Pitman's theory and practice of commerce: A complete guide to methods and machinery of business (Rev. ed.). London: Pitman.
Παραπομπή Chicago StyleHeelis, Frederick 1868-. Pitman's Theory and Practice of Commerce: A Complete Guide to Methods and Machinery of Business. Rev. ed. London: Pitman.
Παραπομπή MLAHeelis, Frederick 1868-. Pitman's Theory and Practice of Commerce: A Complete Guide to Methods and Machinery of Business. Rev. ed. London: Pitman.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.