When looking for references about the rapture one must remember several points.

1. In the Tribulation people will be saved, and some will be martyred.
2. If there is a Post-Tribulational Rapture, there would be:
   1. References to the saints in tribulation, persecuted by the Antichrist.
   2. No references to the saints being removed from the earth.
3. If there is a Pre-Tribulational or Mid-Tribulational Rapture, there would be:
   1. References to the church, believers, Christians, and Saints in the tribulation, being persecuted by the Antichrist.
   2. And references to the church being removed from the earth.

So knowing that references to the believers in the Tribulation do not prove anything about the rapture, we should look for references about the church being removed prior to the time of wrath. Here is what the early church fathers said about the rapture:

• Shepard 150 AD
• The writer, after escaping a huge terrifying beast with four colors on its head (white, red, black and gold), met a virgin in his vision. "like a bride going froth from a bride-chamber, all in white...I recognized from the former visions that it was the church." the virgin explained that she escaped destruction from the beast (the Great Tribulation) because of God's special deliverance. "Thou hast escaped a great tribulation because thou hast believed and at the sight of such a huge beast hast not doubted. Go therefore and declare to the Elect of the Lord His mighty deeds and say to them that this beast is a type of the great tribulation which is to come. If ye therefore prepare yourselves and with your whole heart turn to the Lord in repentance, then shall ye be able to escape it, if your heart is pure and blameless." After explaining to him that "the golden color stands for you who have escaped from this world," the virgin concluded her messages with, "Now ye know the symbol of the great tribulation to come. But if ye are willing, it shall be nothing." 
   
• Victorinus 240AD
• Commentary on the Apocalypse 6.14 - "'And the heaven withdrew as a scroll that is rolled up.' For the heaven to be rolled way, that is, that the Church shall be taken away. "And the mountain and the islands were moved from their places." Mountains and islands removed from their places intimate that in the last persecution all men departed from their places; that is, that the good will be removed, seeking to avoid the persecution."
• Commentary on the Apocalypse 15.1 - "And I saw another great and wonderful sign, seven angels having the seven last plagues; for in them is completed the indignation of God.' For the wrath of God always strikes the obstinate people with seven plagues, that is, perfectly, as it is said in Leviticus; and these shall be in the last time, when the Church shall have gone out of the midst." 
   
• Cyprian 250 AD
• Epistle 55 - The Antichrist is coming, but above him comes Christ also. The enemy goeth about and rageth, but immediately the Lord follows to avenge our suffering and our wounds. The adversary is enraged and threatens, but there is One who can deliver us from his hands." It is significant that he did not write about enduring the persecution of the Antichrist. Rather, Cyprian promised that Christ "is One who can deliver us from his hands." 
• Cyprian Speaking of the immanency of the Rapture, he wrote, "Who would not crave to be changed and transformed into the likeness of Christ and to arrive more quickly to the dignity of heavenly glory." After telling his readers that the coming resurrection was the hope of the Christian, he points out that the Rapture should motivate us as we see the last days approaching. Cyprian says that "we who see that terrible things have begun, and know that still more terrible things are imminent, may regard it as the greatest advantage to depart from it as quickly as possible." Referring to his hope of the approaching Rapture, he encouraged his readers as follows: "Do you not give God thanks, do you not congratulate yourself, that by an early departure you are taken away, and delivered from the shipwrecks and disasters that are imminent?" Cyprian concludes his comments on the translation of the saints with these words: "Let us greet the day which assigns each of us to his own home, which snatches us hence, and sets us free from the snares of the world, and restores us to paradise and the kingdom" (Treatises of Cyprian - 21 to 26?).
   
• Ephraim the Syrian 373 AD
• On The Last Times 2 -  ...because all saints and the elect of the LORD are gathered together before the Tribulation which is about to come and be taken to the LORD...