参考:
Batthyany, A., "Logotherapy and Existential Analysis." Viktor Frankl Institute, Accessed June 3, 2020.
Selva, J., "Logotherapy: Viktor Frankl's Theory of Meaning." PositivePsychology, Updated May 28, 2020.
Schulenberg, S. et al, "Logotherapy for Clinical Practice." Psychotherapy Theory, Research, Practice, Training, 2008.