TY  - RPRT
TI  - Using the EM-algorithm for survival data with incomplete categorical covariates.
AU  - S R Lipsitz
AU  - J G Ibrahim
PY  - 1996
DO  - 10.1007/bf00128467
UR  - https://pubmed.ncbi.nlm.nih.gov/9384645/
ID  - 9384645
ER  -