One of the best things I figured out that at least in the last 70 years or so ago it's pretty easy to find the "first" or foundational paper for a particular construct where they have to explain their notation for the first reader or they have the vibe of working with the new idea in the raw rather than 40 years later where it is matured. One example I use for this is hamming codes where some of the recent examples or explanations don't build it from first principles, but the original articles do explain it very clearly.