TY  - RPRT
TI  - Multiplicative Systems: I.
AU  - C J Everett
AU  - S Ulam
PY  - 1948
DO  - 10.1073/pnas.34.8.403
UR  - https://pubmed.ncbi.nlm.nih.gov/16588820/
ID  - 16588820
ER  -