@misc{Świętochowski_Zbigniew_On,
 author={Świętochowski, Zbigniew},
 howpublished={online},
 publisher={nakł. UMCS},
 language={eng ; fre},
 type={artykuł},
 title={On Second Order Cauchy’s Problem in a Hilbert Space with Applications to the Mixed Problems for Hyperbolic Equations, II},
 keywords={matematyka},
}