Perhaps you should try some spelling variations:
invited lecturers » invited lectures, invited lecture
berkeley invited » berkeley infrared, berkeley david, berkeley notes
berkeley six » berkeley unix, berkeley son, berkeley xi
six lectures » _ lectures, six letters

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 invited lecturers ) OR ( berkeley six lectures )).
• Adding a wildcard symbol may retrieve word variants: (( berkeley invited lecturers ) or ( berkeley six lectures ))*.