Operation Backfire Tests at Altenwalde/Cuxhaven V2ROCKET.COM - Operation Backfire at Cuxhaven/Altenwalde
Operation Backfire: Volume I: https://archive.org/stream/Reportonoperati1Grea#page/n0/mode/2up Volume II: https://archive.org/details/Reportonoperati2Grea Volume III: https://archive.org/details/Reportonoperati3Grea Volume IV: https://archive.org/details/Reportonoperati4Grea Volume V: https://archive.org/details/Reportonoperati5Grea
WO 229/63/7: Use of captured enemy equipment for scientific research. There are 120+ pages related to BACKFIRE in this SHAEF file. You can download WO 229/63 for free from TNA - WO 229/63/7 starts at p.897 of WO-229-63_1.pdf.