@article{MEM_2010_39_1_a40,
     author = {{\CYRI}{\cyrs}{\cyrm}{\cyra}{\cyri}{\cyrl}{\cyro}{\cyrv}{\cyra}-{\CYRI}{\cyrs}{\cyru}{\cyrf}{\cyro}{\cyrv}{\cyra}, {\CYRB}{\cyra}{\cyrh}{\cyrs}{\cyre}{\cyrn} and {\CYRI}{\cyrs}{\cyru}{\cyrf}{\cyro}{\cyrv}, {\CYRR}{\cyri}{\cyrd}{\cyrv}{\cyra}{\cyrn}},
     title = {{\CYRG}{\cyro}{\cyrl}{\cyrya}{\cyrm}{\cyra} {\cyri}{\cyrd}{\cyre}{\cyrya} {\textendash} {\cyrv}{\cyrs}{\cyre} {\cyro}{\cyrshch}{\cyre} {\cyrs} {\cyrm}{\cyra}{\cyrl}{\cyrk}{\cyra} {\cyrp}{\cyro}{\cyrp}{\cyru}{\cyrl}{\cyrya}{\cyrr}{\cyrn}{\cyro}{\cyrs}{\cyrt}},
     journal = {Mathematics and Education in Mathematics},
     pages = {332--339},
     publisher = {mathdoc},
     volume = {39},
     number = {1},
     year = {2010},
     language = {bg},
     url = {http://geodesic.mathdoc.fr/item/MEM_2010_39_1_a40/}
}