What are the anime/manga references in Gintama In the anime of Gintama, there are several references made directly or indirectly to other works in anime and manga.
for example in the first/second episode they make a reference to Ashita no Joe, similarly Itachi's quote from Naruto is used in episode 25. 

I would like to know what are the works that gintama makes references to in order to fully understand the parody they are doing.
There are hardly any lists around that list them by episode, but if you want the lists, there is one on the wikia, though it is complete, it just lists them.

However, a better one, albeit being a little incomplete is available on tvtropes. This list is incomplete but it lists them in order according to the references.