H.  Singh, Menka,, Srivastava, P., and Singh, V., ?Effect of nitrogen addition on the architecture and biomass allocation of two invasive plant species (Ageratum conyzoides L. and Parthenium hysterophorus L.)?, Proceedings of the National Academy of Sciences India Section B-Biological SciencesProceedings of the National Academy of Sciences India Section B-Biological Sciences, vol. 81, pp. 348-358, 2011.