Introduction
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PII: S1071-9091(09)00012-6
doi:10.1016/j.spen.2009.03.005
© 2009 Elsevier Inc. All rights reserved.
PII: S1071-9091(09)00012-6
doi:10.1016/j.spen.2009.03.005
© 2009 Elsevier Inc. All rights reserved.