Do you have any pointers to papers describing how vote auditing techniques extend to liquid democracy? The Google paper doesn't even acknowledge the problem, m

Do you have any pointers to papers describing how vote auditing techniques extend to liquid democracy? The Google paper doesn't even acknowledge the problem, much less describe a solution, and most of the other papers I've read on the topic are either extremely handwavy on the technical details of privacy or make the same assumption as Google, that its good enough to hide votes from the participants but 'the system' still knows.