If you cannot find what you need in the public domain and cannot create it yourself, you need to get permission to use the work of others. If you don't, you could get slapped with a lawsuit.
Getting Permission tackles the permission process head on. The book shows you whom to ask for permission, as well as when and how much to expect to pay. Comprehensive and easy to read the book covers:
This cutting edge book may be the only one on the market to cover website permissions and
information. It includes agreements--both tear-outs and on floppy disk--for acquiring
authorization to use text, photographs, artwork, and music.
Getting Permission will help you obtain rights, permissions and clearance--and stay out of legal hot water.