Ref. Richard Stibbons in 171213 MMDigest.

"The Welte-Mignon: Its Music and Musicians," the immense rollography
by Charles Davis Smith and Richard James Howe, published by Vestal
Press for AMICA (C)1994, page 396, lists these twelve Welte-Mignon
reproducing piano roll performances of pieces composed and played by
Werner Janssen:

X-7108  At the Fireplace (7/25)
Y-6773  Itching Fingers (7/24)
Y-75058 Itching Fingers (7/24) (6773 renumbered)
B-6758  Lady Butterfly Ballet (6/24)
C-6813  "Lady Butterfly" Selection (8/24)
X-7159  Love's Plaint (8/25)
B-6783  March Mignonne (7/24)
B-6735  Ragamuffin (4/24)
Y-75105 Ragamuffin (4/24) (6735 renumbered)
X-7155  Tango Espagnole (9/25)
B-6720  Valsette (5/24)
B-6830  Vanishing Lane, The (9/24)

YouTube performances of Werner Janssen piano rolls are found at

Welte 75105, Ragamuffin: https://www.youtube.com/watch?v=cbCbXWosU54 
Ampico 66903, Valsette: https://www.youtube.com/watch?v=PoqLQ57GzdY 

Robbie Rhodes
Etiwanda, California