1. Baškarada, S., & Koronios, A. (2013). Data, information, knowledge, wisdom (DIKW): A semiotic theoretical and empirical exploration of the hierarchy and its quality dimension. Australasian Journal of Information Systems, 18(1).
2. Doty, R. W. (1998). The five mysteries of the mind, and their consequences. Neuropsychologia, 36(10), 1069–1076.
3. Engel, G. L. (1964). Grief and grieving. AJN the American Journal of Nursing, 64(9), 93–98.
4. Fischer, J. M., Kane, R., Pereboom, D., & Vargas, M. (2007). Four views on free will. .
5. Janet, P. (1928). Fear of action as an essential element in the sentiment of melancholia. Clark University Press.