Guarda crater

地球撞擊資料庫. （原始内容存档于2015-05-05）.  Monteiro, J. F. The Guarda Circular Structure: A Possible Complex Impact Crater. Abstracts of the Lunar and Planetary Science

maintained by David Rajmon for Impact Field Studies Group, USA Impact Meteor Crater Viewer（页面存档备份，存于互联网档案馆） Google Maps Page with Locations of Meteor Craters