F.  Boufahja, Hedfi, A., Amorri, J., A{\"?}ssa, P., Beyrem, H., and Mahmoudi, E., ?{An assessment of the impact of chromium-amended sediment on a marine nematode assemblage using microcosm bioassays.}?, Biological trace element research, vol. 142, pp. 242?55, 2011.