Perhaps you should try some spelling variations:
"eleven supplementary services" » "eleven supplementary exercises", "level supplementary services", "selected supplementary services", "cleaner supplementary services"
"eleven supplementary series" » "level supplementary series", "selected supplementary series", "cleaner supplementary series", "eleven supplementary queries", "eleven supplementary steroids", "eleven supplementary studies"

Try widening your search to All Fields.

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• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"eleven supplementary series\") OR (\"eleven supplementary services\"))".
• Removing quotes may allow a broader search: (( eleven supplementary series ) OR ( eleven supplementary services )).
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