Tài liệu tham khảo WikiPedia: Soth_Polin http://www.thomasbeller.com/debrisofvisible.html http://muse.jhu.edu/login?uri=/journals/manoa/v016... http://www.tufs.ac.jp/common/fs/ase/cam/res/lit/ot... https://web.archive.org/web/20111107102325/http://... https://web.archive.org/web/20160304112857/http://...
