Rhododendron, Azaleen & HortensienHartwig Schepker, Wolfgang Spethmann, Lothar Heft, Deutsche Rhododendron-Gesellschaft · First published 2015Open the Tome
Rhododendron und Immergruene Laubgehoelze (Rhododendrons and Evergreen Shrubs)Johann Berg, Lothar Heft · First published 1991Open the Tome
Der RhododendronparkTitus E. Czerski, Lothar Heft, Gartenbauamt Bremen · First published 1986Open the Tome
