Presenting a conceptual framework for an HIV prevention and care continuum and assessing the feasibility of empirical measurement in Estonia: A case study - Uuskula, A.; Vickerman, P.; Raag, M.; Walker, J.; Paraskevis, D; Eritsyan, K.; Sypsa, V; Lioznov, D.; Avi, R.; Des Jarlais, D. (PLoS One, 2020)