@misc{_Rules,
 howpublished={online},
 publisher={Polski Rejestr Statków},
 language={eng},
 type={e-książka},
 title={Rules for the classification and construction of sea-going ships. Pt. 4, Stability and subdivision, 2018 January},
 keywords={statki, stabilność, normy, wpisanie do rejestru},
}