Reference books at jumble sales (7)

I believe the answer is:

atlases

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'reference books' is the definition.
'atlases' can be an answer for 'books' (I've seen this before). I'm unsure of the 'reference' bit.

'at jumble sales' is the wordplay.
'jumble' is an anagram indicator.
'sales' is an anagram of 'lases'.
'at'+'lases'='ATLASES'

Can you help me to learn more?

(Other definitions for atlases that I've seen before include "Sea-salt (anag)" , "Books of maps" , "navigation aids" , "Sea salt (anag.)" , "Collected charts" .)

I've seen this clue in the Sydney Morning Herald.

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