TY - BOOK AU - Gardner,Martin TI - Aha! Aha! insight SN - 0894540017 AV - QA95 .G23 U1 - 793.7/4 PY - 1978/// CY - New York PB - Scientific American KW - Mathematical recreations KW - Local KW - Problem Solving KW - Puzzles N1 - Bibliography: p. 171-173 ER -