Eusebius of Cesarea writes (Church History, Book 3, Chapter 39)
In these words, it is noteworthy that Papias lists the name John twice. The first time he includes John with Peter, James, Matthew and the other apostles; he obviously means the evangelist. The second time, in a new sentence, he includes John in another category, which is different from that of the apostles; he places Aristion before him and expressly calls him a presbyter. This proves the report true that in Asia two disciples had the same name, and that in Ephesus two tombs were erected, each of which still bears the name John. This must be taken into account. For it is probable that, if one does not want to think of the first John, the second saw the revelation that went under the name of John. John's name, the second has seen the revelation that goes under John's name. Papias, whom we have just quoted, confesses, received the teachings of the apostles from their disciples, and heard Aristion and the presbyter John personally.
The thesis has been disputed; see SE anwer to Who wrote the Book of Revelation?
My question: Are there any independent sources available that support Eusebius thesis that John the Disciple and John the Elder were two different persons? I read in aforementioned article: "But Zahn and most Catholic writers agree that Dionysius was mistaken about the tomb". I could not identify the citation; in the writings of Dionysius I have only found passages about the tomb of Jesus. Have the two tombs in Ephesos been mentioned or even been identified?