TY  - RPRT
TI  - The "optional cross-over design" for randomized controlled trials.
AU  - E Ernst
AU  - K L Resch
PY  - 1995
DO  - 10.1111/j.1472-8206.1995.tb00526.x
UR  - https://pubmed.ncbi.nlm.nih.gov/8617415/
ID  - 8617415
ER  -