Randell, D. A., Cui, Z. and Cohn, A. G.: 1992, "A spatial logic based on regions and connection," Proc. 3rd Int. Conf. on Knowledge Representation and Reasoning, Morgan Kaufmann, San Mateo, pp. 165-176. Available at: https://www.dpi.inpe.br/gilberto/references/cohn_rcc.pdf http://www.ontologyrepository.com/CommonCoreOntologies/Mid/GeospatialOntology tangential part of An immaterial entity im1 is a tangential part of some immaterial entity im2 iff im1 is a spatial part of im2 and there exists some immaterial entity im3 such that im3 externally connects with im1 and im3 externally connects with im2. Given a stronger temporal interpretation, this property may be transitive. For more info please refer to https://github.com/BFO-ontology/BFO-2020/tree/master/src/owl/temporal%20extensions.