Practical Solutions for Managing Optimum C and N content in Agricultural Soils IV : international conference 2007 held in Prague, in June 20th to 22th 2007 / Czech University of Life Sciences Prague, Crop Research Institute, Prague ; K. Voříšek et al. .  Prague :  Czech University of Life Sciences, Department of Microbiology, Nutrition and Dietetics,  2007 .  183 s.