[Android] 스터디

https://acaroom.net/ko/blog/youngdeok/%EC%97%B0%EC%9E%AC-%EC%BD%94%ED%8B%80%EB%A6%B0-%ED%94%84%EB%A1%9C%EC%A0%9D%ED%8A%B8-02-1%EB%8B%A8%EA%B3%84-%EA%B8%B0%EB%B3%B8%EC%A0%81%EC%9D%B8-%EC%84%A4%EA%B3%84%EC%99%80-%ED%99%94%EB%A9%B4-%EA%B5%AC%EC%84%B1

https://academy.realm.io/kr/posts/constraintlayout-it-can-do-what-now/

RxJava

https://dev-daddy.tistory.com/26

파일 업로드

https://march3samwuli.tistory.com/entry/Retrofit-2%EB%A1%9C-Http%ED%86%B5%EC%8B%A0-%EA%B5%AC%ED%98%84-%EC%8B%9C%EA%B0%84%EC%9D%84-%EB%8B%A8%EC%B6%95%ED%95%B4%EB%B3%B4%EC%9E%90

http://reactivex.io/

https://www.youtube.com/watch?v=w5Qmie-GbiA