TY  - RPRT
TI  - Helical vs spiral.
AU  - P M Silverman
AU  - K Corboy
AU  - R K Zeman
PY  - 1994
DO  - 10.2214/ajr.162.5.8192801
UR  - https://pubmed.ncbi.nlm.nih.gov/8192801/
ID  - 8192801
ER  -