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Any of the monsters that drop the Museum quest items (scroll fragments, pottery shards) can also drop the untranslated tome.
However, it is a MUCH rarer drop than the other two (and why you only need one for the quest.
My advice on the museum quests is to NOT take the quest until you have the needed items for it.
I have a secure at my house that I use for these 3 items and when it gets near full, THEN I go and turn them all in at once.
Makes it easier than trying to get a SPECIFIC turn-in drop.