Thực đơn
Henry_DraperThực đơn
Henry_DraperLiên quan
Tài liệu tham khảo
WikiPedia: Henry_Draper http://www.saburchill.com/HOS/astronomy/033.html http://www.naic.edu/~gibson/draper/ http://www.naic.edu/~gibson/draper/photos.html http://americanhistory.si.edu/archives/d8121.htm https://archive.org/details/orionnebula00crob https://commons.wikimedia.org/wiki/Category:Henry_...