extra wordspacing before and after punctuation marks. The conventions are: One space follows sentence-ending punctuation mark (period, question mark, or
Truss, Lynne. Eats, Shoots & Leaves: The Zero Tolerance Approach to Punctuation North American. Toronto: Gotham Books. 2003. ISBN 1592400876. . 查看维基词典中的词条「apostrophe」。
with three handles. Everson, Michael. L2/09-425: Proposal to encode six punctuation characters in the UCS (PDF). 2009-12-05 [2018-03-24]. (原始内容存档 (PDF)于2016-04-07)
Boulton, Mark. Five simple steps to better typography - Part 2: Hanging punctuation. Journal. Mark Boulton, typography designer. 2005-04-18 [2011-03-13]