• Austin, M.P., Groves, R.H., Fresco, L.M.F. & Kaye, P.E. (1985) Relative growth of six thistle species along a nutrient gradient with multispecies competition. Journal of Ecology, 73, 667684.
  • Bakker, J.P., Olff, H., Willems, J.H. & Zobel, M. (1996) Why do we need permanent plots in the study of long-term vegetation dynamics. Journal of Vegetation Science, 7, 147156.
  • Cahill, J.F. Jr (2002) What evidence is necessary in studies which separate root and shoot competition along productivity gradients? Journal of Ecology, 90, 201205.
  • Cheplick, G.P. & Chui, T. (2001) Effects of competitive stress on vegetative growth, storage, and regrowth after defoliation in Phleum pratense. Oikos, 95, 291299.
  • Cheplick, G.P. & Gutierrez, C.M. (2000) Clonal growth and storage in relation to competition in genets of the rhizomatous perennial Amphibromus scabrivalvis. Canadian Journal of Botany, 78, 537546.
  • Fone, A.L. (1989) Competition in mixtures of the annual Hypochoeris glabra and perennial H. Radicata. Journal of Ecology, 77, 484494.
  • Goldberg, D.E. (1987) Neighborhood competition in an old-field plant community. Ecology, 68, 12111223.
  • Gurevitch, J., Wilson, P., Stone, J.L., Teese, P. & Stoutenburgh, R.J. (1990) Competition among old-field perennials at different levels of soil fertility and available space. Journal of Ecology, 78, 727744.
  • Hooper, D.U. (1998) The role of complementarity and competition in ecosystem responses to variation in plant density. Ecology, 79, 704719.
  • Liira, J. & Zobel, K. (2000) The species richness-biomass relationship in herbaceous plant communities: what difference does the incorporation of root biomass data make? Oikos, 91, 109114.
  • McConnaughay, K.D.M. & Coleman, J.S. (1999) Biomass allocation in plants: ontogeny or optimality? A test along three resource gradients. Ecology, 80, 25812593.
  • Moora, M. & Zobel, M. (1996) Effect of arbuscular mycorrhiza on inter- and intraspecific competition of two grassland species. Oecologia, 108, 7984.
  • Nötzold, R., Blossey, B. & Newton, E. (1997) The influence of below ground herbivory and plant competition on growth and biomass allocation of purple loosestrife. Oecologia, 113, 8293.
  • Reynolds, H.L. & D’Antonio, C. (1996) The ecological significance of plasticity in root weight ratio in response to nitrogen. Opinion. Plant and Soil, 185, 7597.
  • Tilman, D. (1989) Ecological experimentation: strengths and conceptual problems. Long Term Studies in Ecology. Approaches and Alternatives (ed. G. E.Likens), pp. 137157. Springer, New York.
  • Whigham, D.F. (1984) The effect of competition and nutrient availability on the growth and reproduction of Ipomoea hederacea in an abandoned old field. Journal of Ecology, 72, 721730.