@article{lejpt30149,
 author={Vasilev, J. and Kehayova-stoycheva, M.},
 year={2017},
 title={Sales analysis by the rectangle method},
 journal={Leonardo Electron. J. Pract. Technol.},
 volume={16},
 number={30},
 pages={149-160},
 url={http://lejpt.academicdirect.org/A30/149_160.pdf}
}