B. Knechtle, E. Eichenberger, C. A. Rüst, R. Lepers, T. Rosemann, and V. O. Onywera, “The aspect of nationality and performance in a mountain ultra-marathon: The ‘Swiss Alpine Marathon’”, J. Hum. Sport Exerc., vol. 7, no. 4, pp. 748–762, Dec. 2012.