After checking both my notes and roll collection, I can come up
with only one pseudonym used exclusively by J. Lawrence Cook on his
QRS rolls.  That is Sid Laney.  Another possibility is Eubie Jones,
found only on US rolls, never on QRS.

However, there are a number of QRS pseudonyms adopted by Cook
after originally having been used by others.  These are Ted Baxter,
Pep Doyle, Walter Redding, Harold Scott and Jeff Watters.

In addition, later rolls attributed to these artists are said to
actually have been done by Cook: Victor Arden, Max Kortlander,
Fats Waller, Pete Wendling.

Drawing on his remarkable talent and years of experience, Cook could
easily duplicate the piano styles of just about anyone using his
direct method of punching a master roll, which eliminated the need
for an actual recording session.

Cook produced for QRS a number of "Personality Series" rolls, omitting
his name altogether and labeled "As Played by" (or its equivalent),
followed by one of these names: Frankie Carle, Carmen Cavallaro, Duke
Ellington, Jack Fina, Errol Garner, Eddie Heywood, Gene Kerwin,
Liberace, Tiny Little, Jr., Johnny Maddox, Jelly Roll Morton, George
Snowhill, Art Tatum, Cy Walter, Maurice Whitney, Roger Williams,
Teddy Wilson, Bob Zurke.

This list is not guaranteed to be 100% accurate or complete.  It will
be interesting to see what others have to say.

A tremendous wealth of J. Lawrence Cook biographical information,
pictures and music may be found at

  http://www.doctorjazz.co.uk/page11.html

Jeffrey R. Wood