Board Thread:General Discussion/@comment-24494906-20151221214237/@comment-30068215-20160122211158

IMO, numbers below 20 should be written in words, because most numbers over 20 consists of hyphens (like twenty-one, eighty-eight etc). Numbers between 13 and 19 don't have hyphens.

Yeah, Chapter article names have colons, so it should be Re:.