Effects of L-carnitine supplementation on physical performance and energy metabolism of endurance-trained athletes: a double-blind crossover field study - Colombani, P.; Wenk, C.; Kunz, I.; Krahenbuehl, S.; Kuhnt, M.; Arnold, M.; Frey-Rindova, P.; Frey, W.; Langhans, W. (European Journal of Applied Physiology, 1996)