Siegerpferde aus Oldenburg - Hengste-Stuten-Sportpferde Roland Ramsauer & Claus Schridde, 1991, hardcover, 208 pgs., b/w & color photos, text in German. Excellent overview of the Oldenburg from 1580 to present, includes sections on the historical development of the breed, important stallion lines (including thoroughbred, French, Holsteiner and Hanoverian influences), important mare families, notable Oldenburg sporthorses, champion stallions (siegerhengste) since 1968 w/photos, champion mares (siegerstute) since 1968 w/photos.