1. Amey J, Houston D, Tennyson A, McAllister A (2001) Census of the Snares crested penguin (Eudyptes robustus) breeding population. Southland Conservancy, Invercargill, New Zealand
2. Bazett HC (1920) An analysis of the time-relations of electrocardiograms. Heart-a J Study Circ 7:353–370
3. Berens P (2009) CircStat: a MATLAB toolbox for circular statistics. J Stat Softw 31:1–21
4. Buckley R (2004) Environmental impacts of ecotourism. CABI, Wallingford
5. Burger J (2002) Tourism and ecosystems. In: Douglas I (ed) Causes and consequences of global climate change, vol 3. Encyclopedia of global environmental change. Wiley, Chichester, pp 597–609