Resolution Sensitivity of a Compound Terrain Derivative as Computed from LiDAR-Based Elevation Data. - Ralph K. Straumann; Ross S. Purves (AGILE Conf., 2007)

Delineation of Valleys and Valley Floors. - Ralph K. Straumann; Ross S. Purves (GIScience, 2008)

Computation and Elicitation of Valleyness. - Ralph K. Straumann; Ross S. Purves (Spatial Cogn. Comput., 2011)