German standard methods for the examination of water, waste water and sludge - Biological-ecological analysis of water (group M) - Part 1: Determination of the saprobic index in running waters (M 1)— 80 стр.
Water quality - Guidelines for the selection of sampling methods and devices for benthic macroinvertebrates in fresh waters (ISO 10870:2012); German version EN ISO 10870:2012— 36 стр.