TY  - RPRT
TI  - Linear Partial Differential Equations with Analytic Coefficients.
AU  - F John
PY  - 1943
DO  - 10.1073/pnas.29.3-4.98
UR  - https://pubmed.ncbi.nlm.nih.gov/16578100/
ID  - 16578100
ER  -