Puerta Yepes, M. E., and G. I. Loaiza Ossa. “On a Minimal Operator Ideals Defined by Means of Interpolation Spaces”. Ingeniería Y Ciencia, vol. 3, no. 6, Dec. 2007, pp. 63-89, https://publicaciones.eafit.edu.co/index.php/ingciencia/article/view/441.