https://resource-allocation.biomedcentral.com/articles/10.1186/s12962-020-00221-z
https://resource-allocation.biomedcentral.com/articles/10.1186/s12962-020-00226-8
https://resource-allocation.biomedcentral.com/articles/10.1186/s12962-020-00222-y
https://resource-allocation.biomedcentral.com/articles/10.1186/s12962-020-00218-8
https://resource-allocation.biomedcentral.com/articles/10.1186/s12962-020-00225-9
https://resource-allocation.biomedcentral.com/articles/10.1186/s12962-020-00224-w