http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
"The book is an outgrowth of my research ... activities in Bell telephone laboraties. Its first draft was prepared in connection with courses of lectures in the laboratories 'Out-of-hour' program. Courses were given in 1933-34 and 1934-35, for which the lectures were mimeographed under the title 'Electromagnetic theory and its applications.' A third course was given in 1941-42, when the notes were revised under the present title."--Pref.