TY  - RPRT
TI  - Difficulties in conducting a prospective outcome study.
AU  - Jetske Ultee
AU  - Johan W van Neck
AU  - Jean Bart Jaquet
AU  - Steven E R Hovius
PY  - 2003
DO  - 10.1016/s0749-0712(03)00023-4
UR  - https://pubmed.ncbi.nlm.nih.gov/12945643/
ID  - 12945643
ER  -