Solimini, A. G., Candoso, A. C.
, Carstensen, J., Free, G., Heiskanen, A.-S., Jepsen, N., Noges, P., Poikane, S. & van de Bund, W. (2008).
The Monitoring of Ecological Status of European Freshwaters. In P. Quevauviller, U. Borchers, K. C. Thompson & T. Simonart (Eds.),
The Water Framework Directive: Ecological and Chemical Status Monitoring (pp. 29-60). John Wiley & Sons Ltd.
http://www.amazon.co.uk/gp/reader/0470518367/ref=sib_dp_pt#reader-page