SMS Blücher - Wikipedia
Germany 28 cm/50 (11) SK L/50 - NavWeaps
List of battleships of Germany - Wikipedia
WW2 German SPG Prototypes Archives - Tank Encyclopedia
28 cm SK C/28 naval gun - Wikipedia
SK L/45 (380 mm) - War Thunder Wiki
Projekt P.1000 - Tank Encyclopedia
Germany 28 cm/52 (11) SK C/28 - NavWeaps
Germany 30.5 cm/50 (12) SK L/50 - NavWeaps
The Wells Brothers' Battleship Index: Debunking the Later H-class Battleships
The most powerful naval guns of World War II