Perhaps you should try some spelling variations:
"theory and equations library" » "theory and equations linear", "theory and equations binary", "theory and equations glossary"
"theory and equation library" » "theory and education library", "theory and emulation libbrary", "theory and equation linear"

Try widening your search to All Fields.

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: "((\"theory and equation library\") OR (\"theory and equations library\"))".
• Removing quotes may allow a broader search: (( theory and equation library ) OR ( theory and equations library )).
• Adding a wildcard symbol may retrieve word variants: (("theory and equation library") OR ("theory and equations library"))*.