L. F. D. Lopes, F. P. Machado, F. G. Lopes, M. P. Lima, V. M. F. Costa, and D. Della Mea da Silva, “An analysis of the marketing environment of a metal mechanical industry under the Porter’s perspective”, ReA UFSM, vol. 6, no. 1, pp. 103–118, Apr. 2013.