| 其他書名 | For the Practical Assistance of Agents, Contractors, Engineers, Estimating, Commercial and Technical Correspondents, Merchants, Representatives, and Salesman |
| 出版 | J.W. Arrowsmith, Limited, 1920 |
| URL | http://books.google.com.hk/books?id=zDwxAQAAMAAJ&hl=&source=gbs_api |