TY  - RPRT
TI  - Learning curve in endoscopic sinus surgery.
AU  - S C Marks
PY  - 1999
DO  - 10.1016/s0194-5998(99)70409-2
UR  - https://pubmed.ncbi.nlm.nih.gov/9949355/
ID  - 9949355
ER  -