TY  - RPRT
TI  - Marijuana use by heroin abusers as a factor in program retention.
AU  - M Ellner
PY  - 1977
DO  - 10.1037//0022-006x.45.4.709
UR  - https://pubmed.ncbi.nlm.nih.gov/886059/
ID  - 886059
ER  -