Discussion paper presented at a meeting of the OECD Short-term Economic Statistics Expert Group, Paris, 26-27 June 2003. http://www.oecd.org/dataoecd/12/60/2789033.pdf, accessed on 7 August 2003.
http://www.oecd.org/dataoecd/12/60/2789033.pdf,2003年8月7日存取。