Journal (New Ulm)(英语:The Journal (New Ulm)). November 30, 2017 [January 7, 2023]. (原始内容存档于2023-01-07). Sblendorio, Peter. 'No Exit' star David Rysdahl on
ISBN 0-13-516972-0. traditional Bourne shell family / history and development. In-ulm.de. [10 December 2018]. (原始内容存档于2020-04-14). This is the AT&T Software Technology
the Spanish Armada, history’s most confused and misunderstood battle. Wes Ulm, Harvard University (页面存档备份,存于互联网档案馆) The Defeat of the Spanish Armada. Insight