Kosuke Kato Masatoshi Sakawa Keiichi Ishimaru Satoshi Ushiro Operation Planning of District Heating and Cooling Plants Considering Contract Violation Penalties. 185-192 2009 13 JACIII 3 http://www.fujipress.jp/finder/xslt.php?mode=present&inputfile=JACII001300030003.xml db/journals/jaciii/jaciii13.html#KatoSIU09