TY  - DATA
AU  - Nelsen, Roger B.
TI  - Proofs without words: exercises in visual thinking 
T2  - Classroom Resource Materials, 
SN  - 9781470451875 (online)
PY  - 1993///
CY  - Washington, D.C.
PB  - The Mathematical Association of America
KW  - Mathematics
N1  - Includes bibliographic references (p. 145-152) and index
UR  - https://doi.org/10.1090/clrm/001
ER  -