Has a dinosaur egg ever been found?

Could you elaborate on the likelihood of discovering a dinosaur egg? Have any dinosaur eggs been found in the past, and if so, where were they discovered? What were the conditions surrounding the discovery, and how were they preserved over time? Furthermore, do scientists believe that there are still undiscovered dinosaur eggs waiting to be found, and if so, where might they be located? Lastly, what methods do researchers use to identify and study dinosaur eggs once they are discovered?