N. Dunstone. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 372 (2025):
20130340+(Sep 28, 2014)
J. Bojanowski. University of Twente Faculty of Geo-Information and Earth Observation (ITC), P.O. Box 217, 7500 AE Enschede, The Netherlands, (January 2014)