Physiological comparisons of elite male Visma Ski Classics and national level cross-country skiers during uphill treadmill roller skiing - Sagelv, E. H.; Engseth, T.; Pedersen, S.; Pettersen, S. A.; Mathisen, G.; Heitmann, K. A.; Welde, B.; Thomassen, T. O.; Stöggl, T. L. (Frontiers in Physiology, 2018)