@misc{Feller_William_(1906–1970)_On_1952,
 author={Feller, William (1906–1970)},
 editor={Polskie Towarzystwo Matematyczne},
 copyright={Rights Reserved - Restricted Access},
 address={Cracov},
 howpublished={online},
 year={1952},
 publisher={[s.n.]},
 language={eng},
 language={eng},
 type={Text},
 title={On positivity preserving semigroups of transformations on C[r₁, r₂]},
}