Balderas, Fausto, Eduardo Fernandez, Claudia Gómez Santillán, Gilberto Rivera, Laura Cruz-Reyes, and Nelson Rangel. 2016. “Uncertainty Modelling for Project Portfolio Problem Using Interval Analysis”. International Journal of Combinatorial Optimization Problems and Informatics 7 (3), 20-27. https://ijcopi.org/ojs/article/view/24.