Update README.md

Author: zpardos

README.md

@@ -11,7 +11,7 @@ a middleware backend is required by Learning Tools Interoperability (LTI). Our [
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 ## Paper
-To credit this library, please cite our CHI'23 paper:
+To credit this system, please cite our CHI'23 paper:
 
 Zachary A. Pardos, Matthew Tang, Ioannis Anastasopoulos, Shreya K. Sheel, and Ethan Zhang. 2023. OATutor: An Open-source Adaptive Tutoring System and Curated Content Library for Learning Sciences Research. In *Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems (CHI '23)*. Association for Computing Machinery, New York, NY, USA, Article 416, 1–17. [https://doi.org/10.1145/3544548.3581574](https://doi.org/10.1145/3544548.3581574)
 ```