Pimentel, C. E., V. V. Gouveia, T. A. Carvalho, C. M. Machado, and A. K. S. Soares. “Attitudes Toward Heavy Metal Scale: An Example of Type-Likert Scale Development”. Per Musi, no. 37, Apr. 2018, doi:10.35699/2317-6377.2017.5169.