Rubio Martín, Gracia, and Prosper Lamothe Fernández. “Real Option in Biotechnological Firms Valuation. An Empirical Analysis of European Firms”. Journal of Technology Management & Innovation, vol. 1, no. 2, June 2006, pp. 27-52, https://www.jotmi.org/index.php/GT/article/view/art4.