De Courcy, Ken: Dubblekross & Simulkross ©1955 George Armstrong, The Magic Wand, London, England Softcover, saddle-stitched, 5.5x8.5", 16 pages

Image courtesy eBay seller EarlofMansfield

Comments: Gems of Magic No. 2. From the Foreword: "Many methods have been devised for the classical effect wherein three coins pass invisibly through space to join three more. Dubbelkross and Simulkross are two further variations on the same theme, but, not only are the the methods altered, the effects are, too. In fact, Dubbelkross represents the first attempt (as far as I know) at giving this transposition a definite climax. Simulkross does not pretend to give a startling climax, but it interesting because coins pass simultaneously from each side."

Contents (Partial contents from book images):

3 Foreword (Ken De Courcy)
4 Dubblekross
4 - The Effect
4 - The Requirements
5 - The Presentation
11 Simulkross