Bennett-Brandt, Sonya. "Cheat Sheet for Using the Free Planetarium Software ' Stellarium' - from David Bruning". OER Commons. Institute for the Study of Knowledge Management in Education, 12 Dec. 2017. Web. 18 Mar. 2019. <https://www.oercommons.org/authoring/26215-cheat-sheet-for-using-the-free-planetarium-softwar>.
Bennett-Brandt, S. (2017, December 12). Cheat Sheet for Using the Free Planetarium Software ' Stellarium' - from David Bruning. OER Commons. Retrieved March 18, 2019, from https://www.oercommons.org/authoring/26215-cheat-sheet-for-using-the-free-planetarium-softwar.