1. Human alteration of the global nitrogen cycle: Sources and consequences;PM Vitousek;Ecological Applications,1997
2. Millennium Ecosystem Assessment (2005) Ecosystems and human well-being, vol. 1. Current state and trends: Findings of the condition and trends working group (Millennium Assessment Series). Washiington, DC: Island Press.
3. Upward trend in soluble phosphorus loadings to Lough Neagh despite phosphorus reduction at sewage treatment works;RH Foy;Water Research,1995
4. Eutrophication of aquatic ecosystems: Bistability and soil phosphorus;SR Carpenter;Proceedings of the National Academy of Sciences of the USA,2005
5. Agronomic phosphorus imbalances across the world’s croplands;GK MacDonald;Proceedings of the National Academy of Sciences of the USA,2011