1. Adu, KO, 2018. National health insurance and treatment- seeking behaviour in selected Regions of Ghana. Unpublished Doctoral thesis, University of Cape Coast, Cape Coast.
2. Adu, KO, 2019b. National Health Insurance Scheme renewal in Ghana: Does waiting time at health insurance registration office matter? MPRA paper 91961, University Library of Munich, Germany https://mpra.ub.uni-muenchen.de/91961/.
3. National health insurance and the choice of delivery facility among expectant mothers in Ghana