N. Nenov
1111 School Jokes- 3000 Knock - Knock Jokes
- British Physics Olympiads - Book 1
- British Physics Olympiads - Book 2
- Canadian Physics Olympiads - Preparation Program 1994 - 1999
- Canadian Physics Olympiads - Preparation Program 1999 - 2004
- Canadian Physics Olympiads - Preparation Program 2004 - 2009
- Chemistry Olympiads 1997-2008 Solutions of the Preparatory Problems
- Chemistry olympiads 1997-2009 preparatory Problems
- Christmas Surprise - coloring Book
- International Chemistry Olympiads
- International Physics Olympiads - Book 2 (1992 - 2002)