Crittenden, P., Scrimgeour, C., Minnullina, G., Sutton, M., Tang, Y., & Theobald, M. (2015). Lichen response to ammonia deposition defines the footprint of a penguin rookery. Biogeochemistry, 122(2-3), https://doi.org/10.1007/s10533-014-0042-7