@ARTICLE {DIELS:2001, title = {Temporal variations in plant delta 13C values and implications for using the 13C technique in long-term soil organic matter studies}, author = {Diels, J. and Vanlauwe, B. and Sanginga, N. and Coolen, E. and Merckx, R. }, journal = {Soil Biology and Biochemistry}, year = {2001}, volume = {33}, pages = {1245--1251}, issn = {0038-0717}, }