A Supplement to Clarke's Dictionary of Practical Materia Medica
by Peter David Fraser
Clarke's Dictionary is available in 3 volume book form from most homopathic suppliers. It is included in most Materia Medica computer programs (Isis, Encyclopedia Homeopathica or ReferenceWorks) Or is available on line (by subscription) at The Homeopathy International Website
There are many Provings of new remedies on this site.
Homeopathy Home has a page of links to homopathic provings.
Another valuable List of Provings is maintained by Jorg Wichmann.
There is a Database of Provings maintained by Jeremy Sher's Dynamis School.
For more general homopathic links go to The Homopath's Webshelf