Although he was familiar with the metaverse of Neal Stephenson's novel Snow Crash, Rosedale has explained that his eyesight of digital worlds predates that book, and that he done early virtual earth experiments during his faculty many years at the University of California, San Diego, where by he analyzed physics. Br Med J 1:1249–1250. Kato I, Akhmedkhanov A, Koenig K, Toniolo PG, Shore RE, Riboli E. 1997.