International Law: A Dictionary （页面存档备份，存于互联网档案馆）, by Boleslaw Adam Boczek; Scarecrow Press, 2005; page 239: "The issue whether it is possible or useful to establish a legal boundary between airspace and outer space has been debated in the doctrine for quite a long time. . . . no agreement exists on a fixed airspace – outer space boundary . . ."
Squire, Tom, U.S. Standard Atmosphere, 1976, Thermal Protection Systems Expert and Material Properties Database (NASA), September 27, 2000 [2011-10-23], （原始内容存档于2011-10-15）
Squire, Tom, U.S. Standard Atmosphere, 1976, Thermal Protection Systems Expert and Material Properties Database (NASA), September 27, 2000 [2011-10-23], （原始内容存档于2011-10-15）
International Law: A Dictionary （页面存档备份，存于互联网档案馆）, by Boleslaw Adam Boczek; Scarecrow Press, 2005; page 239: "The issue whether it is possible or useful to establish a legal boundary between airspace and outer space has been debated in the doctrine for quite a long time. . . . no agreement exists on a fixed airspace – outer space boundary . . ."
