TY  - RPRT
TI  - A case study of student-directed discussion in four problem-based tutorial groups.
AU  - L Wilkerson
AU  - J P Hafler
AU  - P Liu
PY  - 1991
DO  - 10.1097/00001888-199109000-00048
UR  - https://pubmed.ncbi.nlm.nih.gov/1930538/
ID  - 1930538
ER  -