E. Kruggel & G. Gerbasevskis. Die Munzen des Herzogtums Kurland. 2000. Coins of the Duchy of Courland.

The best study of the coins of the Duchy of Courland. Professional, very detailed catalog of types and varieties of all coins minted from 1578 to 1780.
Riga 2000 dimensions: 177x248 mm, pages: 222, hardcover, German language, new.

Courland (Kurland), Friedrich und Wilhelm Kettler 1596-1616. Shilling 1607, Mitau, Kopicki 4021 (R3), Haljak 1652, Silver 18 mm, weight 0,88 g., Condition XF+, small edge damage, sharp details, surface with mint shine, very rare in this condition

Courland (Kurland), Friedrich Kasimir Kettler 1682-1698. Ort (18 Gröscher / Tymph) 1694, Mitau mint, Kruggel/Gerbasevskis 4.8.1.1, Kopicki 4075 (R7), Neumann 311, Haljak 90, Silver 29 mm, weight 5,11 g., Condition aVF, nice patina, small scratches, typical shallow struck, one of the two - much more rare variety with full date

Courland / Kurland. Friedrich Kettler 1587-1642. 3 Groschen (Dreigröscher) 1598, Mitau, Kopicki 4042 R4, Iger KuW.98.1.c R2, Silver 21 mm, weight ca. 2,3 g., Condition PCGS MS 63, nice golden patina on obverse, sharp relief details, mint state - shiny specimen, rare in this state of preservation
Variety with title ending CVR, digits date 98, unseparated and close together.
Aw: MONE . A - RG . CV. R (CVR mistakenly separated by a dot) / Rw: III / GROS . AR . TR / DVCVM CV / . ET . SE . / . 98 .