Birch, C. E. (1928). Fundamentals of business practice: Laboratory material for use in junior business training courses. Gregg Publishing Co..
Lua i Stíl Chicago (17ú heag.)Birch, Clarence E. Fundamentals of Business Practice: Laboratory Material for Use in Junior Business Training Courses. New York [etc.]: Gregg Publishing Co., 1928.
Lua MLA (8ú heag.)Birch, Clarence E. Fundamentals of Business Practice: Laboratory Material for Use in Junior Business Training Courses. Gregg Publishing Co., 1928.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.