Perhaps you should try some spelling variations:
"nijhoff book untitled 2001" » "nijhoff book entitled 2001", "nijhoff book intitled 2001", "nijhoff book entituled 2001", "nijhoff book untitled 2", "nijhoff boston untitled 2001", "nijhoff op untitled 2001"
"nijhoff book titles 2006" » "nijhoff boston titles 2006", "nijhoff op titles 2006", "nijhoff book entitled 2006", "nijhoff book intitled 2006"

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: (("nijhoff book titles 2006") OR ("nijhoff book untitled 2001")).
• Removing quotes may allow a broader search: (( nijhoff book titles 2006 ) or ( nijhoff book untitled 2001 )).
• Adding a wildcard symbol may retrieve word variants: (("nijhoff book titles 2006") or ("nijhoff book untitled 2001"))*.