References

[1] “Pumping lemma for context-free languages,” Wikipedia, Jul. 30, 2024.
[Online]. Available: https://en.wikipedia.org/wiki/Pumping_lemma_for_context-free_languages

[2] S. B. Davies, “Lecture 11 – Proving that languages are not context-free,” CS360: Formal Languages, University of Waterloo, 2022.
[Online]. Available: https://cs.uwaterloo.ca/~s4bendav/files/CS360S22Lec11.pdf

[3] Explanation of the pumping lemma justification via repeated nonterminals, Computer Science StackExchange.
[Online]. Available: https://cs.stackexchange.com/questions/99612/justification-for-the-pumping-lemma-of-context-free-languages