Expert conference on cancer pain assessment and classification, the need for international consensus: working proposals on international standards

S Kaasa, G Apolone, P Klepstad, JH Loge, MJ Hjermstad, O Corli, F Strasser, T Heiskanen, M Costantini, V Zagonell, Mogens Grønvold, R Fainsinger, MP Jensen, JT Farrar, H McQuay, N E Rothrock, J Cleary, C Deguines, A Caraceni