I. Hemmer, M. Hemmer, G. Obermaier, and R. Uphues, “Spatial Orientation: An Empirical Study on the Relevance of the Competency Area Spatial Orientation in the View of Society and Experts”, ZGD, vol. 36, no. 1, pp. 17–32, Mar. 2008, doi: 10.60511/zgd.v36i1.212.