BRANTH S., HAMBRAEUS L., PIEHL-AULIN K., ESSÉN-GUSTAVSSON B., ÅKERFELDT T., OLSSON R., STRIDSBERG M., and RONQUIST G. “Metabolic Stress-Like Condition Can Be Induced by Prolonged Strenuous Exercise in Athletes”. Upsala Journal of Medical Sciences, vol. 114, no. 1, July 2009, pp. 12-25, doi:10.1080/03009730802579778.