We searched MEDLINE, EconLit and Scopus, unpublished and grey literature, hand-searched four specialty journals, examined references of relevant studies, and contacted key informants.



MEDLINE
We searched MEDLINE, EconLit and Scopus, unpublished and grey literature, hand-searched four specialty journals, examined references of relevant studies, and contacted key informants.



EconLit
We searched MEDLINE, EconLit and Scopus, unpublished and grey literature, hand-searched four specialty journals, examined references of relevant studies, and contacted key informants.



Scopus