Perhaps you should try some spelling variations:
petroov » petrov (Expand Search), petruoov (Expand Search), petrooov (Expand Search), peroov (Expand Search)
petrois » petris (Expand Search), petruois (Expand Search), petroois (Expand Search), perois (Expand Search), petros (Expand Search), petrovs (Expand Search), petrows (Expand Search)
petriiv » petruiiv (Expand Search), petroiiv (Expand Search), periiv (Expand Search)
petr » petru (Expand Search), petro (Expand Search), per (Expand Search)
petri » petrui (Expand Search), petroi (Expand Search), peri (Expand Search)
petroi » petruoi (Expand Search), petrooi (Expand Search), peroi (Expand Search), petro (Expand Search), petrov (Expand Search), petrow (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 ((petroov OR (periov OR petriiv)) OR (petrois OR ((petr OR petri) OR (petroi OR peter)))) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petroov OR (periov OR petriiv)) OR (petrois OR ((petr OR petri) OR (petroi OR peter)))) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petroov OR (periov OR petriiv)) OR (petrois OR ((petr OR petri) OR (petroi OR peter)))) o.s.*.