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Lucassen, Friedrich, Wolfgang Pritzkow, Martin Rosner, Fernando Sepúlveda, Paulina Vásquez, Hans Wilke, and Simone A. Kasemann. "The Stable Isotope Composition of Nitrogen and Carbon and Elemental Contents in Modern and Fossil Seabird Guano From Northern Chile – Marine Sources and Diagenetic Effects." PLoS One 2017.

Lucassen, Friedrich, et al. "The Stable Isotope Composition of Nitrogen and Carbon and Elemental Contents in Modern and Fossil Seabird Guano From Northern Chile – Marine Sources and Diagenetic Effects." PLoS One 2017.