You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: operation ((reinhold OR erhard) OR richard)~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "operation ((reinhold OR erhard) OR richard)".
• Adding a wildcard symbol may retrieve word variants: operation ((reinhold OR erhard) OR richard)*.