[55] Leitner System(암기에 관련된 시스템)에 관한 소개글

[1]: https://en.wikipedia.org/wiki/Flashcard "Flashcard"
[2]: https://en.wikipedia.org/wiki/Sebastian_Leitner "Sebastian Leitner"
[3]: https://en.wikipedia.org/wiki/Spaced_repetition "Spaced repetition"
[4]: https://ncase.me/remember/
[5]: https://www.youtube.com/watch?v=uvF1XuseZFE
[6]: https://ncase.me/remember/pdf/leitner.pdf​