TY  - RPRT
TI  - THE SINGULARITIES OF INTEGRABLE STRUCTURALLY STABLE PFAFFIAN FORMS.
AU  - I Kupka
PY  - 1964
DO  - 10.1073/pnas.52.6.1431
UR  - https://pubmed.ncbi.nlm.nih.gov/16591241/
ID  - 16591241
ER  -