You can find sources related to this through Library Search and other library research databases. One source you might read is chapter 2 of this ebook. As it is a chapter in an edited book, the Harvard reference for this source would be:
Holland, K. (2019) 'An introduction to the Roper–Logan–Tierney model for nursing, based on Activities of Living', in K. Holland and J. Jenkins (eds) Applying the Roper-Logan-Tierney model in practice. 3rd edn. Elsevier, pp. 17-39.
