@article{Mayer2013definition,
author={Mayer, R.V.},
title={DEFINITION OF LEVEL OF ABSTRACTNESS, COMPLEXITY AND INFORMATIONAL CONTENT OF VARIOUS SUBJECTS SCHOOL TEXTBOOK OF PHYSICS},
journal={Standards and Monitoring in Education},
publisher={INFRA-M Academic Publishing LLC.},
year={2013},
pages={19-27},
volume={1},
issue={6},
}