Image from Magic, white and black; or, The science of finate and infinite life, containing practical hints for students of occultism (1890) by Franz Hartmann
Includes the names: Franz Hartman, Franz Hartmann, Franz Hartmann M.D., M. D. Frazn Hartmann
Franz Hartmann is currently considered a "single author." If one or more works are by a distinct, homonymous authors, go ahead and split the author.
Franz Hartmann is composed of 5 names. You can examine and separate out names.