Coors, A. & De Meester, L. (2008) Synergistic, antagonistic and additive effects of multiple stressors: predation threat, parasitism and pesticide exposure in Daphnia magna. Journal of Applied Ecology, 45, 1820–1828.
The authors of Coors & De Meester (2008) apologize for the mistake in equation 2 as given in print. It should read:
The correct formula was used for all calculations in the study, so this correction has no impact on the results or interpretations.