Sinks for nitrogen inputs in terrestrial ecosystems: a meta-analysis of 15N tracer field studies. - Templer PH; Mack MC; Chapin FS 3rd; Christenson LM; Compton JE; Crook HD; Currie WS; Curtis CJ; Dail DB; D'Antonio CM; Emmett BA; Epstein HE; et al. (Ecology, 2012)