Barenreiter Urtext BA9606 - Johannes Brahms Albumblatt for Piano. During his research for the Brahms Horn Trio (BA 9435), Christopher Hogwood came across a source to which George Bozarth had drawn attention in the Spring of 2011 and which had not been available for any previous edition. The source consists of a one-page autograph of a piano piece which the young Brahms wrote in a guest book. Twelve years later Brahms re-used this literal “Albumblatt” (untitled by Brahms) in his horn trio.