Mutation testing is not so suited for literature, because of the recursive structures. I once counted 600,000 unique absolute Xpaths for in documents corpus. it is the problem of combinatorial explosion.
but even for literature, if you have no corpus, mutation is probably Ok. But you need to make sure the mutation including recursive, structures not just values. And you have to have a good justification for why, in your case, mutation is complete enough and more effective than, say, Risk based testing
Rick