Perhaps you should try some spelling variations:
petriuov » petrov (Expand Search), peteriuov (Expand Search), petruiuov (Expand Search), petroiuov (Expand Search)
periov » perov (Expand Search)
peri » per (Expand Search)
petroov » peteroov (Expand Search), petruoov (Expand Search), petrooov (Expand Search)
petruo » peteruo (Expand Search), petruuo (Expand Search), petrouo (Expand Search)
petri » peteri (Expand Search), petrui (Expand Search), petroi (Expand Search)
petr » peter (Expand Search), petru (Expand Search), petro (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 petriuov) OR petriuov) OR periov) OR ((petruo OR (peri OR petri)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((((petroov OR petriuov) OR petriuov) OR periov) OR ((petruo OR (peri OR petri)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((((petroov OR petriuov) OR petriuov) OR periov) OR ((petruo OR (peri OR petri)) OR petr)) o.s.*.