Ka Boon Ng Chiu Wo Choi Martin Henz A Software Engineering Approach to Constraint Programming Systems. 167-175 2002 conf/apsec/2002 APSEC http://csdl.computer.org/comp/proceedings/apsec/2002/1850/00/18500167abs.htm db/conf/apsec/apsec2002.html#NgCH02