Bit of leg certain to be like old book (9)

I believe the answer is:

calfbound

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'be like old book' is the definition.
I don't know anything about this answer so I can't tell whether this works.

'bit of leg certain' is the wordplay.
'bit of leg' becomes 'calf' ('calf' is part of 'leg').
'certain' becomes 'bound' (as in the phrase 'it's bound to be').
'calf'+'bound'='CALFBOUND'

'to' is the link.

Can you help me to learn more?

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

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