Perhaps you should try some spelling variations:
"popisom: the warhol sixties" » "podpisom: the warhol sixties", "opisom: the warhol sixties", "prepisom: the warhol sixties"
"popisem: the warhol sixties" » "popise: the warhol sixties", "opisem: the warhol sixties", "popitem: the warhol sixties"

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"popisom: the warhol sixties\") OR (\"popisem: the warhol sixties\"))".
• Removing quotes may allow a broader search: (( popisom: the warhol sixties ) OR ( popisem: the warhol sixties )).
• Adding a wildcard symbol may retrieve word variants: (("popisom: the warhol sixties") OR ("popisem: the warhol sixties"))*.