Weber, Jörg, and Martin Sandtner. “The Use of Surface Structures in the Description of Urban Spaces: A Contribution to the Mapping, Analysis and Evaluation of Sustainable Yrban Development: The Example of Munich”. Raumforschung Und Raumordnung | Spatial Research and Planning, vol. 57, no. 5-6, Sept. 1999, pp. 410–417, https://doi.org/10.1007/BF03184509.