(EN) The Age of the marvelous, Hood Museum of Art, 1991, p. 436, ISBN 9780944722107.
«This book, reflecting his many interests, is a collection of scientific mysteries embracing everything from geometrical demonstrations to illusionistic stage sets, music, perpetual motion machines, and anamorphoses. According to Bettini, the natural world abounds in mathematical delights such as spider webs and the honeycombs of bees. From these creations of nature can be drawn geometrical principles useful for mechanical, optical, and artistic designs.»
