Kirkham, F. W., Tallowin, J. R. B., Sanderson, R. A., Hoppe, G. M., Goodyear, J. (2002). Role of organic fertilizers in the sustainable management of semi-natural grasslands, II - Botanical studies.   BGS Occasional Symposium, Conservation Pays? Reconciling environmental benefits with profitable grassland systems. Proceedings of the joint British Grassland Society / British Ecological Society Conference, University of Lancaster, 15-17 April 2002, Frame, J. ISBN:0905944402, 36, 153-155