ZIENKOV: 1880-1910, the magnificent study collection (almost 1500) notable for the many complete sheets and reconstructed settings, including 1879-88 Second issue, 8th printing 3k. cherry-red two sheets (4x6), 1887 Fourth issue 3k. green sheet (4x6), 1891 Ninth issue 1k. and 2k. sheets (12x6), 1898 Eleventh issue (June) 3k. gold-bronze imperf. sheet reconstructed from the blocks of four and a vertical strip of four and a complete perf. sheet, 1898 (late) Thirteenth issue 3k. essays (6), 1899-1900 Seventeenth issue, 2nd printing (1900) 3k. sheet (8x6, comprising two tête-bêche panes of 24), 1907 Twenty-second issue 3k. blue-green block (5x2) two positions inverted, 1909 (Sept.) Twenty-third issue 1k. pane (7x7) and 2k. bronze Post Office sheet comprising two panes (7x7) têtê-bêche (only 15 sheets printed, ex Fabergé and Lentz), 1909 (late) Twenty-fourth issue 2k. bronze Printer's sheet comprising two panes (7x7) (ex Fabergé and Lentz), a unique opportunity