Soto-Rodríguez, E., and E. Maíz-Vázquez. “Implications of Including Non-executives’ Perception in the Executive Opinion Survey: A Hierarchical Bias Effect in the Global Competitive Index”. American Journal of Management, vol. 16, no. 3, Sept. 2016, https://articlegateway.com/index.php/AJM/article/view/1874.