TY  - RPRT
TI  - Simple summary calculations.
AU  - J S Bulman
AU  - J F Osborn
PY  - 1989
DO  - 10.1038/sj.bdj.4806727
UR  - https://pubmed.ncbi.nlm.nih.gov/2920120/
ID  - 2920120
ER  -