| 其他書名 | The Eighteenth Lecture Delivered in the Pitcairn-Crabbe Lecture Series Delivered in the Stephen Collins Foster Memorial, Tuesday, March 6, 1951 |
| 出版 | University of Pittsburgh Press, 1951 |
| URL | http://books.google.com.hk/books?id=4FApAQAAMAAJ&hl=&source=gbs_api |