Ryuichi Takahashi Noriyoshi Yoshida Diagonal Examples for Design Space Exploration in an Educational Environment CITY-1. 71-73 1999 conf/mse/1999 MSE http://csdl.computer.org/comp/proceedings/mse/1999/0312/00/03120071abs.htm db/conf/mse/mse1999.html#TakahashiY99