Good to know, thanks. If I may expand the topic of this thread to sources of inexpensive books, I will mention Dover, especially Dover Thrift Editions
http://store.doverpublications.com/by-subject-literature-dover-thrift-editions.html and the Math and Science club
http://store.doverpublications.com/by-subject-science-and-mathematics.html , which is free to join and has a nice printed catalog. Edward R. Hamilton
http://www.edwardrhamilton.com/ has many discounted books, but since the topics span a wide range, I would not leave a catalog with a child.
