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