8Airola, T. M. and Buchholz, K. 1984. Species structure and soil characteristics of five urban sites along the New Jersey Palisades. Urban Ecology. 8: 149～164.
9Bremner, J. M. 1996. Nitrogen-total. In Sparks, D. L., Page, A. L., Helmke, P. A., Loeppert, R. H.,Soltanpour, P. N., Tabatabai, M. A. and Johnston, C. T. (eds.) Methods of Soil Analysis. Part 3.Chemical Methods. Soil Science Society of America, Madison, Wisconsin, USA. pp. 1085～1 121.
10Institute of Soil Science, the Chinese Academy of Sciences. 1978. Soil Physical and Chemical Analysis (in Chinese). Shanghai Scientific and Technological Publishing House, Shanghai. pp. 132～517.
