Dr. George Lenchner · Georg Langenhoff · Georg Langenhorst · Georg Lenzen
Glenwood Pubns Inc · Mathematical Olympiads
| title | ISBN-13 (ISBN-10) | year of publica- tion |
|---|---|---|
| Creative Problem Solving in School Mathematics, Revised and Expanded 2nd Edition | 978-1-882144-10-5 (1-882144-10-4) | 2005 |
| Mathematical Olympiad Contest Problems for Children | 978-0-9626662-0-9 (0-9626662-0-3) | 1990 |
| Math Olympiad Contest Problems for Elementary and Middle Schools | 978-0-9626662-1-6 (0-9626662-1-1) | 1996 |