TY  - RPRT
TI  - A Simple Second Order Differential Equation with Singular Motions.
AU  - N Levinson
PY  - 1948
DO  - 10.1073/pnas.34.1.13
UR  - https://pubmed.ncbi.nlm.nih.gov/16588775/
ID  - 16588775
ER  -