Gerosa, Daniel, Christoph Alexander Rüst, Thomas Rosemann, and Beat Knechtle. 2015. “Participation and Performance Trends in 161km Ultra-Marathons in Terms of Nationality: A Retrospective Data Analysis of Worldwide Participation from 1998-2011”. Journal of Human Sport and Exercise 9 (2):592-615. https://doi.org/10.14198/jhse.2014.92.01.