Perhaps you should try some spelling variations:
berkeley unix » berkeley usa
unix lectures » union lectures, six lectures, munich lectures
berkeley xi » berkeley _, berkeley ca, berkeley d
xi lectures » i lectures, ii lectures, xi lecture

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: (( berkeley unix lectures ) OR ( berkeley xi lectures )).
• Adding a wildcard symbol may retrieve word variants: (( berkeley unix lectures ) or ( berkeley xi lectures ))*.