| Digest Nr | Subject and Author |
|---|
 |
| 2022.01.22.02 | Roll Boxes for Arburo, Bursens, Popper, Eich, Etc., from Roger Wiegand |
| 2021.06.06.01 | Popper "Stella" Reproducing Piano of 1908, from Uwe Gernert |
| 2021.05.31.02 | Popper "Stella" Reproducing Piano of 1908, from Jim Miller |
| 2017.12.14.01 | Ibach Pianos Delivered to Welte, Hupfeld & Popper, from Marc Widuch |
| 2012.02.10.03 | Popper Roland "Swanee Whistle" Operation, from Dale F. Rowe |
| 2012.02.09.01 | Popper Roland "Swanee Whistle" Operation, from Roger Wiegand |
| 2011.10.18.03 | Seek Popper Konzertist Orchestrion Rolls, from Wayne Finger |
| 2011.05.29.05 | FS: Popper Piano Spool Box & Action, from Donald MacKenzie |
| 2011.03.28.02 | Popper "Roland" Orchestrion, from Bernt Damm |
| 2010.10.12.14 | Popper Orchestrion Note Ranges, from Wayne Finger |
| 2009.03.13.04 | Popper Gladiator Recording on San Sylmar CD, from Jack M. Conway |
| 2009.02.20.06 | Seek Popper Gladiator Recording, from Brian Smith |
| 2006.08.06.02 | Seek Rolls for Popper Welt Konzertist Piano, from Wayne Finger |
| 2006.06.30.07 | FS: Popper Welt Konzertist in Seattle, from Eric Shoemaker |
| 2003.06.26.05 | Source of Popper Rolls, from Jurgen Goering |
| 2003.06.25.12 | Popper Mechanism Plays Konzertist Rolls, from Carl Kehret |
| 2002.09.08.06 | FS: Popper Welt Piano Konzertist, from Philip Jamison |
| 1999.04.20.12 | FS: Popper Konzertist & Phillips Duca, from Dirk Tiedt |
| 1996.04.22.06 | Popper Valves, from Philip Jamison |
| 1996.04.19.05 | Popper Konzertist, from Philip Jamison |
| 1996.04.15.14 | Popper Valves, from Philip Jamison |
|
