Perhaps you should try some spelling variations:
"testhefte zu poetica" » "beihefte zu poetica", "testheft i poetica", "testheft ii poetica", "testhefte la poetica", "testhefte de poetica", "testhefte e poetica"
"geschafte zu poetica" » "geschafte zur poetica", "geschafte fur poetica", "geschafte _ poetica", "geschafte la poetica", "geschafte de poetica", "geschafte e poetica"
"leithefte zu poetica" » "leithefte la poetica", "leithefte de poetica", "leithefte e poetica", "beihefte zu poetica", "lesehefte zu poetica"

Try widening your search to All Fields.

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("leithefte zu poetica") OR ("testhefte zu poetica"))) OR ("geschafte zu poetica")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"leithefte zu poetica\") OR (\"testhefte zu poetica\"))) or (\"geschafte zu poetica\"))".
• Removing quotes may allow a broader search: (((( leithefte zu poetica ) OR ( testhefte zu poetica ))) or ( geschafte zu poetica )).
• Adding a wildcard symbol may retrieve word variants: (((("leithefte zu poetica") OR ("testhefte zu poetica"))) or ("geschafte zu poetica"))*.