The world broke in two : Virginia Woolf, T.S. Eliot, D.H. Lawrence, E.M. Forster and the year that changed literature / Bill Goldstein. (OCLC #970042762)

Subject Heading Manual section H 620 on establishing chronological subject headings says:

Establish headings for centuries, decades, or years using words, not numbers.

    650 _0 ǂa Nineteen twenty-two, A.D.

It also says:

This differs from the practice for subdivisions where numbers are preferred.

    650 _0 ǂa Literature and society ǂx History ǂy 20th century.