Majgaard, Gunver, Lasse Larsen, Patricia Lyk, and Morten Lyk. “Seeing the Unseen—Spatial Visualization of the Solar System With Physical Prototypes and Augmented Reality”. International Journal of Designs for Learning 8, no. 2 (November 8, 2017). Accessed August 20, 2019. https://scholarworks.iu.edu/journals/index.php/ijdl/article/view/22368.