Perhaps you should try some spelling variations:
"sung and moon letters" » "dung and moon letters", "song and moon letters", "cung and moon letters", "sung and muon letters", "sung and yoon letters", "sung and soon letters"
"sung and mon letters" » "dung and mon letters", "song and mon letters", "cung and mon letters"
"cong and moon letters" » "cong and muon letters", "cong and yoon letters", "cong and soon letters"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("sung and moon letters") or ("cong and moon letters"))) or ("sung and mon letters"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("sung and moon letters") OR ("cong and moon letters"))) OR ("sung and mon letters"))*.
• Removing quotes may allow a broader search: (((( sung and moon letters ) or ( cong and moon letters ))) or ( sung and mon letters ))*.