KENT, RICHARD (1997):
Room 109. The Promise of a Portfolio Classroom.
Boynton/Cook: Portsmouth, New Hampshire.

LEDL, V. (1994):
Kinder beobachten und fördern. Wien.

TOMLINSON, CAROL ANN (2004):
How to differentiate instruction in mixed-ability classrooms.
Moorabbin, Vic: Hawker Brownlow.

LEIBOWITZ, MARIAN (1996):
The heterogeneous classroom [video recording].
Linton Professional Development Corporation.
Salt Lake City, UT: LPD Video Journal of Education.