Rundetaarn: Centuries of Astronomy in Denmark
Includes section on R%c3%a1¸mers works.
http://www.rundetaarn.dk/engelsk/observatorium/history.htm

Catalog of the Scientific Community: Roemer, Ole Christensen
Background data on the scientist.
http://es.rice.edu/ES/humsoc/Galileo/Catalog/Files/roemer.html

Ole R%c3%a1¸mer Museet
Copenhagen museum about his works in astronomy.
http://www.oleroemer.dk/

Wikipedia: Ole R%c3%a1¸mer
Short crosslinked encyclopedic article.
http://www.wikipedia.org/wiki/Ole_Romer

Roemer, Ole
Article from the 1911 Encyclopedia Britannica.
http://64.1911encyclopedia.org/R/RO/ROEMER_OLE.htm