How to find "original papers" on some topic?
As much you deepen your read of papers on a topic, the &quot;first papers&quot; will be cited recurrently.
However, the first paper candidates could be extracted computationally. You could use scientometrics techniques that map most cited works, for example. The most cited works are good candidates to be considered an &quot;original paper&quot;.
Another way is to map the history of a field using visualization techniques. You extract a relevant set of papers in a topic, and then draw citations networks. The papers on the root of the network probably are good candidates to be original papers. And not necessarily have many citations.
A good book to see these techniques is Mapping Scientific Frontiers, from Chaomei Chen. The author presents an interdisciplinary view on science study, focusing on found the scientific frontiers - including finding papers that are disruptive or initiated a whole study field.