Gaubinger, K., Rabl, M., Swan, S., & Werani, T. (2014). Innovation and product management: A holistic and practical approach to uncertainty reduction (2015th ed.). Springer.
Espinoza, J. A. M., Proano, P. A., Villavicencio, J. R. M., & Villegas, M. A. (2019, December). Extending PESTEL technique to neutrosophic environment for decisions making in business management. Neutrosophic Sets and Systems, 27, 228-231.