00511naa#a2200169#i#450# EN\INFRA-M\bibl\3228 20240703142002.3 1998-0744 20140617b2014####ek#y0engy0150####ca RUS RU Plotting a Trajectory for Modern Natural and Mathematical Education at Middle School Journal article Moscow INFRA-M Academic Publishing LLC. 2014 7 с. Journal article local Tsvetkova Marina S. zh-szf.ru