What is the product of doing research in other countries' literature or author?
The term is “comparative literature”, the study of literatures not confined to one language or country. Comparative literature research usually treats movements or historical periods wider spread than just one nation. For example, the study of the existential view of modern literature would require a scholar to see how the philosophical movement manifested in German literature (Kafka, for example) as well as French, its primary manifestation (the works of Camus, Gide, and of course Sartre); there were existential literary outputs as well in Russia, England, and elsewhere (the American “Bartleby the Scrivener”, for example). Translation theory also must deal with comparative literature, since most readers and scholars cannot master all the literature in its original language. Historical periods, too, require comparative study techniques – the Renaissance period is concerned not only with English writers but with Italian, German, etc., so, say, an examination of Renaissance drama would be comparative – Elizabethan dramatists, to be sure, but also Italian farces, German tragedies, etc. The most challenging comparative studies deal with literature plus another discipline – philosophy, linguistics, sociology, etc.