A. Carnoy: Les Indo-Européens.
Weise: The Language and Character of the Roman People.
I. Taylor: Words and Places.
Skeat: Place-names of Hertfordshire.
G. H. McKnight: English Words and their Background.
M. Müller: Biographies of Words; On Comparative Mythology; Theosophy.
L. Noiré: The Origin and Philosophy of Language.
L. Geiger (translated): Language and its Importance in the History of the Development of the Human Race.
O. Jespersen: The Philosophy of Grammar; Language, its Nature, Development, and Origin.