On metrizability of continuous images of compact ordered spaces Witold Bula — 1984 Fundamenta Mathematicae

Paracompactness in the class of closed images of GO-spaces Witold Bula — 1986 Fundamenta Mathematicae

On compact Hausdorff spaces having finitely many types of open subsets Witold Bula — 1979 Colloquium Mathematicae