Here are entered works on combined physical and digital content that enables interaction with real-world and digital object. Works on entirely digital environments that are experienced by end users are entered under Virtual reality. Works on environments that layer digital content on top of physical environments are entered under Augmented reality.
Here are entered works on trade among nations. Works on foreign trade of specific countries, cities, etc. are entered under headings of the type [place]--Commerce, further subdivided by place, if appropriate. If so subdivided, a second heading is assigned with the place names in reverse positions, e.g. 1. Canada--Commerce--United States. 2. United States--Commerce--Canada.
