TY  - RPRT
TI  - Choosing the best research design for each question.
AU  - D L Sackett
AU  - J E Wennberg
DO  - 10.1136/bmj.315.7123.1636
UR  - https://pubmed.ncbi.nlm.nih.gov/9448521/
ID  - 9448521
ER  -