"February 2018."
Astronomy 2018. , 2019. Web. 22 Feb. 2019.
<http://www.whitakersalmanack.com?id=-118573CITANCHOR>.
"February 2018."
Astronomy 2018. , 2019.
http://www.whitakersalmanack.com/?id=-118573CITANCHOR.
Astronomy 2018
Whitaker's Almanack
January 3, 2019
February 22, 2019
http://www.whitakersalmanack.com/?id=-118573CITANCHOR