Distinct immunohistochemical expression of osteopontin in the adult rat major salivary glands - Nicholas Obermüller; Nikolaus Gassler; Norbert Gretz; Bettina Kränzlin; Sigrid Hoffmann; Helmut Geiger; Stefan Gauer (Journal of Molecular Histology, 2006)

Cordierite III: the site occupation and concentration of Fe3+ - Charles A. Geiger; Helmut Rager; Michael Czank (Contributions to Mineralogy and Petrology, 2000)