The effects of beetroot juice supplementation on exercise economy, rating of perceived exertion and running mechanics in elite distance runners: A double-blinded, randomized study - Balsalobre-Fernandez, C.; Romero-Moraleda, B.; Cupeiro, R.; Peinado, A. B.; Butragueño, J.; Benito, P. J. (PLOS ONE, 2018)