Immuno-endocrine and metabolic responses to long distance ski racing in world-class male and female cross-country skiers - Ronsen, O.; Borsheim, E.; Bahr, R.; Klarlund Pedersen, B.; Haug, E.; Kjeldsen-Kragh, J.; Hostmark, A. T. (Scandinavian Journal of Medicine & Science in Sports, 2004)