The Most Intriguing Evidence that John Used Sources

So far in this going-to-be-substantial thread on the Johannine Writings (Gospel of John;1, 2, and 3 John) I have shown how John is very different from the other Gospels in numerous ways, argued that its account is not based on those of the others three (whether or not the author knew of their existence), yet maintained that he must have had other sources at his disposal that provided him with his stories.  Before detailing what scholars have said about these other sources I need to give the...