Vitaly Telerman Vladimir Sidorov Dmitry Ushakov Problem Solving in the Object-Oriented Technological Environment NeMo+. 91-100 1996 conf/ershov/1996 Ershov Memorial Conference db/conf/ershov/ershov1996.html#TelermanSU96 http://dx.doi.org/10.1007/3-540-62064-8_9