Perhaps you should try some spelling variations:
petrie » petri (Expand Search), petris (Expand Search), petre (Expand Search), petriie (Expand Search), petruie (Expand Search), petroie (Expand Search)
petr » petri (Expand Search), petru (Expand Search), petro (Expand Search)
petroov » petrioov (Expand Search), petruoov (Expand Search), petrooov (Expand Search), petrov (Expand Search)
petriiu » petriiiu (Expand Search), petruiiu (Expand Search), petroiiu (Expand Search)
petroi » petrioi (Expand Search), petruoi (Expand Search), petrooi (Expand Search), petri (Expand Search), petro (Expand Search), petrov (Expand Search)
petruoi » petriuoi (Expand Search), petruuoi (Expand Search), petrouoi (Expand Search)

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: fop ((((petrie OR patrie) OR petr) OR petroov) OR ((petriiu OR (petroi OR petruoi)) OR peter)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petrie OR patrie) OR petr) OR petroov) OR ((petriiu OR (petroi OR petruoi)) OR peter)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petrie OR patrie) OR petr) OR petroov) OR ((petriiu OR (petroi OR petruoi)) OR peter)) o.s.*.