Sources of the puzzles


H.E.Dudeney: Amusements in Mathematics		ISBN 58-13360 "430 puzzles, problems, paradoxes, and brain-teasers presented by a master of mathematical ingenuity". First edition 1917, republished 1958 with additional remarks on british coins and stamps and a note on the game of cricket (for american readers) by Dover Publications, Inc., New York.
Martin Gardner (ed.): Mathematical Puzzles of Sam Loyd, vol. 1 & 2		ISBN 0-486-20498-7 and 486-20709-90 283 puzzles, more than 270 illustrations. A two-volume selection of puzzles from the 1914 Cyclopedia of Puzzles, published 1959 by Dover Publications, Inc., New York.
*Zweistein*		Zweistein is a weekly puzzle corner contained in the Zeit Magazin, which comes with the german newspaper Die Zeit.