Media type: E-Article Title: Combinatorial Optimization Problems with Soft and Hard Requirements Contributor: Eiselt, Horst A.; Laporte, Gilbert imprint: Informa UK Limited, 1987 Published in: Journal of the Operational Research Society Language: English DOI: 10.1057/jors.1987.132 ISSN: 0160-5682; 1476-9360 Origination: Footnote: