J. Keil, D. Edler, L. Kuchinke, und F. Dickmann. Abstracts of the International Cartographic Association, 1, Seite 167. Copernicus Publications, (2019)
S. Chopra, R. Hadsell, und Y. LeCun. Proceedings of the 2005 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR'05) - Volume 1 - Volume 01, Seite 539--546. Washington, DC, USA, IEEE Computer Society, (2005)