I guess, most will agree - the "bible" is
The Complete Guide to Perthshire Paperweights
Colin & Debby Mahoney and Gary & Marge McClanahan
Paperweight Press (Selman) 1997
ISBN (Softcover) 0-933756-24-0
ISBN (Hardcover) 0-933756-27-5
As it was published 1997, obviously weights made after 1997 will not be shown. There have been rumours about an expanded edition, until 2002, but I haven't heard anything definite.
The book frequently shows up on ebay - but in my experience you'll find better deals on JustBooks, Alibris or Amazon.