Nagore Guerra Bilbao and  Clemente Lobato Fraile,  Elaboration and Validation of a Survey about Research on the Characteristics of Mentoring of University Professors’ Lifelong Learning.   journal   = {International Journal of Educational and Pedagogical Sciences}, [online]. World Academy of Science, Engineering and Technology.
    February 2017, vol. 123(3). 635 - 639
    [viewed 06 December 2019]. Available from: https://publications.waset.org/pdf/10006661.