For substantial discussion, including why this isn't the first bug, isn't the origin of the term, and wasn't actually found by Grace Hopper, here's a place to start:

https://news.ycombinator.com/item?id=6359241

For more information, here's a search:

https://www.hnsearch.com/search#request/all&q=bug+hopper

More references here:

https://news.ycombinator.com/item?id=813900