Vasiliou, V. S., Michaelides, M. P., Kasinopoulos, O., & Karekla, M. (2019). Psychological Inflexibility in Pain Scale: Greek adaptation, psychometric properties, and invariance testing across three pain samples. Psychological Assessment, 31(7), 895–904. https://doi.org/10.1037/pas0000705
Vasiliou, V. S. (2017). Acceptance and commitment therapy for primary headache sufferers : a randomized controlled trial. Dissertation: University of Cyprus. Retrieved from https://gnosis.library.ucy.ac.cy/handle/7/39514 The Greek PIPS-II is in Appendix B.