Not everything can be found on the internet. Some interesting information can also be found in books. Here is a list of books with information about burrs and other puzzles

 

Spelen met puzzels, Pieter van Delft en Jack Botermans, De Bezige Bij, 1978. ISBN 90-234-5238-0

Puzzle Craft, Stewart Coffin, Mass. 1985

Puzzels zelf maken en oplossen, Jack Botermans en Jerry Slocum, ADM international, Amsterdam 1986. ISBN 90-697-6026

The puzzling world of polyhedral dissections, Stewart Coffin, Oxford University Press, Oxford 1990

Puzzels Klassiek en Modern, Jack Botermans en Jerry Slocum, Zomer & Keuning Boeken B.V., Ede 1992. ISBN 90-210-0490-9

The book of ingenious & diabolical puzzles, Jack Botermans en Jerry Slocum, Times Books, New York 1994. ISBN 0-8129-2153-4

New wood puzzle designs, James W. Follette, Linden Publishing Inc, Fresno 2001. ISBN 0-941936-57-0