The LC download page is great resource! One thing I recently stumbled upon in parsing these RDF files was a C library, Raptor: https://github.com/dajobe/raptor, (docs: http://librdf.org/raptor/) which aside from being a great RDF parsing tool is also my daughters favorite dino.
The "Rapper" tool specifically was one I used for serializing the subject authorities from ndjson into .ttl. It was a pain to compile so I made a docker-alpine-based image or the built tool so that it would be more streamlined for others (and future me I suppose): https://hub.docker.com/repository/docker/jimfhahn/raptor-rdf-syntax-library Here are the steps that I believe I pre-compiled a couple days ago: http://librdf.org/raptor/INSTALL.html With some helpful flags to the project here: http://librdf.org/raptor/rapper.html I did not try your specific use case but I wonder if some of the optional flags are what you are looking for? Best, Jim
