@article{MEM_2010_39_1_a34,
     author = {{\CYRG}{\cyre}{\cyro}{\cyrr}{\cyrg}{\cyri}{\cyre}{\cyrv}, {\CYRK}{\cyra}{\cyrl}{\cyri}{\cyrn} and {\CYRS}{\cyrt}{\cyra}{\cyrv}{\cyrr}{\cyro}{\cyrv}{\cyra}, {\CYRD}{\cyri}{\cyrm}{\cyri}{\cyrt}{\cyrr}{\cyri}{\cyrn}{\cyra}},
     title = {{\CYRV}{\cyrhrdsn}{\cyrr}{\cyrh}{\cyru} {\cyrd}{\cyrv}{\cyra} {\cyrp}{\cyro}{\cyrd}{\cyrh}{\cyro}{\cyrd}{\cyra} {\cyrz}{\cyra} {\cyrp}{\cyrr}{\cyre}{\cyrp}{\cyro}{\cyrd}{\cyra}{\cyrv}{\cyra}{\cyrn}{\cyre} {\cyrn}{\cyra} {\cyrp}{\cyro}{\cyrn}{\cyrya}{\cyrt}{\cyri}{\cyrya}{\cyrt}{\cyra} {\cyrv} {\cyrk}{\cyru}{\cyrr}{\cyrs}{\cyra} {\cyrp}{\cyro} {\cyrk}{\cyro}{\cyrm}{\cyrp}{\cyryu}{\cyrt}{\cyrhrdsn}{\cyrr}{\cyrn}{\cyra} {\cyrt}{\cyro}{\cyrp}{\cyro}{\cyrl}{\cyro}{\cyrg}{\cyri}{\cyrya}},
     journal = {Mathematics and Education in Mathematics},
     pages = {292--299},
     publisher = {mathdoc},
     volume = {39},
     number = {1},
     year = {2010},
     language = {bg},
     url = {http://geodesic.mathdoc.fr/item/MEM_2010_39_1_a34/}
}