Clay Pipes
Links
The Archaeology of the Clay Tobacco Pipe
http://www.shef.ac.uk/assem/issue6/Cessford_text_web.htm
An article by Craig Cessford from Assemblage, with references and bibliography.
Canadian Clay Tobacco Pipe Industries
http://www.virtlogic.ca/pipe/pipes.html
Dedicated to the 19th century Canadian clay tobacco pipe industry.
Knasterkopf
German society for clay pipe research: publishes an annual journal and holds annual conferences.
Clay Pipes.com
Devoted to the study and dissemination of information about clay tobacco pipes.