Perhaps you should try some spelling variations:
periv » petriv (Expand Search), perv (Expand Search)
peri » petri (Expand Search), per (Expand Search)
petriiv » peteriiv (Expand Search), petriiiv (Expand Search), petroiiv (Expand Search)
petru » peteru (Expand Search), petriu (Expand Search), petrou (Expand Search)
petrui » peterui (Expand Search), petriui (Expand Search), petroui (Expand Search)
petruui » peteruui (Expand Search), petriuui (Expand Search), petrouui (Expand Search)
petr » peter (Expand Search), petri (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 ((petriiv OR periv) OR (((petru OR peri) OR ((petrui OR peteroiui) OR petruui)) OR petr)) o.s.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "fop ((petriiv OR periv) OR (((petru OR peri) OR ((petrui OR peteroiui) OR petruui)) OR petr)) o.s.".
• Adding a wildcard symbol may retrieve word variants: fop ((petriiv OR periv) OR (((petru OR peri) OR ((petrui OR peteroiui) OR petruui)) OR petr)) o.s.*.