adds more data

docs/goods/planks.md

@@ -14,9 +14,23 @@
 ## Production
 
 **Produced By:**
-- Sawmill (Albion)
-- Sawmill (Latium)
+- [Sawmill (Albion)](../buildings/sawmill-albion.md)
+- [Sawmill (Latium)](../buildings/sawmill-latium.md)
+
+## Related Goods
+
+Other construction materials:
+- [Concrete](./concrete.md)
+- [Wattle & Daub](./wattle-daub.md)
+- [Granite](./granite.md)
+- [Marble](./marble.md)
+- [Mosaics](./mosaics.md)
+- [Armor](./armor.md)
+- [Sails](./sails.md)
+- [Ropes](./ropes.md)
+- [Weapons](./weapons.md)
+- [Bricks](./bricks.md)
 
 ## Notes
 
-Planks are a fundamental construction material produced from wood at sawmills. They are available from the very beginning of the game and used extensively in building construction.
+Planks (German: Bretter) are a fundamental construction material produced from wood at sawmills. They are available from the very beginning of the game for both Latium (Liberti) and Albion (Waders) regions, and are used extensively in building construction.