I am looking for a link or reference to the four decrees from Diocletian in 303 re the Roman Persecution?
As far as I am aware, we do not have the original texts of any of the Diocletian edicts. The course of events is recorded, however, by Eusebius in his Church History (c.323-324) and Martyrs of Palestine (after 311), and by Lactantius in his Deaths of the Persecutors (c. 316-321). Our knowledge of the "four edicts" is compiled out of these sources.
It was in the nineteenth year of the reign of Diocletian, in the month Dystrus, called March by the Romans, when the feast of the Saviour's passion was near at hand, that royal edicts were published everywhere, commanding that the churches be leveled to the ground and the Scriptures be destroyed by fire, and ordering that those who held places of honor be degraded, and that the household servants, if they persisted in the profession of Christianity, be deprived of freedom. (Church History 8.2.4)
Next day an edict was published, depriving the Christians of all honours and dignities; ordaining also that, without any distinction of rank or degree, they should be subjected to tortures, and that every suit at law should be received against them; while, on the other hand, they were debarred from being plaintiffs in questions of wrong, adultery, or theft; and, finally, that they should neither be capable of freedom, nor have right of suffrage. (Deaths of the Persecutors 13)
Not long after... a royal edict directed that the rulers of the churches everywhere should be thrown into prison and bonds. (Church History 8.6.8)
Other decrees followed the first, directing that those in prison if they would sacrifice should be permitted to depart in freedom, but that those who refused should be harassed with many tortures. (Church History 8.6.10)
In the course of the second year [=304], the persecution against us increased greatly. And at that time Urbanus being governor of the province, imperial edicts were first issued to him, commanding by a general decree that all the people should sacrifice at once in the different cities, and offer libations to the idols. (Martyrs of Palestine 3)
For further context, the story of the Diocletian persecution is told in Church History chapter 8, and in Lactantius chapters 7-19. See also Wikipedia on Diocletianic Persecution for many other accounts and references.