GA 기본
What is Google Analytics sampling and how to avoid it
https://supermetrics.com/blog/google-analytics-samplingGoogle Analytics - Count Of Sessions Explained
https://www.digishuffle.com/blogs/google-analytics-count-of-sessions-metrics-simplified-series/Google Analytics로 무엇을 할 수 있을까?
https://htaegy.tistory.com/m/5