{{Cite journal| volume = 32| issue = 2| pages = 419–429| last1 = Errecalde| first1 = O.| last2 = Seidl| first2 = M.| last3 = Campbell| first3 = P.G.C.| title = Influence of a low molecular weight metabolite (citrate) on the toxicity of cadmium and zinc to the unicellular green alga Selenastrum capricornutum: An exception to the free-ion model| journal = Water Research| date = 1998}}