Who first defined/coined The Double-Spending Problem? The Double-Spending problem is a variant of the Byzantine Generals Problem which has a nice write up by Lamport, Shostak and Pease. But who first coined/defined the specific Double-Spending problem? Or linked the BGP to the digital currency domain? Does there exist a proper academic write up, defining the problem, that predates bitcoin?

I searched for a bit and can only find write ups after Nakamoto's publication.
Does there exist a proper academic write up, defining the problem, that predates bitcoin?


Google ngrams shows the phrase being used as early as the 1970s but that is probably not in the context of digital currencies.

The earliest reference I could easily find is in several articles in "Advances in Cryptology - CRYPTO '93"  

For example in "Untraceable Off-Line Cash in Wallet with Observers" by Stefan Brands.

Since several articles mention double spending I expect the coinage of this phrase in this context is older than 1993.

However there were no mentions in CRYPTO '92.