Firth, Chris (2002) The use of gross and net margins in the economic analysis of organic farms. UK Organic Research 2002 Conference, Aberystwyth, 26-28 March 2002. In: Powell, Jane and et al., (Eds.) Proceedings of the UK Organic Research 2002 Conference, Organic Centre Wales, Institute of Rural Studies, University of Wales Aberystwyth, pp. 285-288.