There doesn't seem to be an author named Gustav Leunbach. It's possible you may be referring to a different author. Can you provide more context or check the spelling of the author's name?
Gustav Sack has written:
'Prosa, Briefe, Verse'
Gustav Leunbach has written:
'A probabilistic measurement model for assessing whether two tests measure the same personal factor' -- subject(s): Educational tests and measurements
Thomas F. Sack has written:
'A complete guide to building and plant maintenance' -- subject(s): Industrial housekeeping, Buildings, Plant maintenance, Maintenance
Gustav Suits has written:
'Flames on the wind'
Gustav Weidanz has written: 'Gustav Weidanz'
Gustav Hagemann has written: 'Gustav Hagemann'
Gustav Hegi has written: 'Alpenflora'
Gustav Frenssen has written: 'Gravelotte'
Gustav Niemann has written: 'Machine elements'
Gustav Leonhardt has written: 'Bach:Goldberg Variations'
Gustav Metzman has written: 'Cincinnati and Ohio'
Gustav Schwab has written: 'Gods and heroes'
Gustav Lampmann has written: 'Ernst Balser'
Gustav Kortum has written: 'Textbook of electrochemistry'
Gustav Ploetz has written: 'English vocabulary'
Gustav Lindau has written: 'Die Algen ...'