Part of a series of similar puzzles - the answer to one will give you the type of thinking required for the others.
What's the next letter in this series? What's the relationship?
G
J
T
J
J
J
A
M
W
J
J
Z
M
F
J
A
A
U
R
J
C
G
B
G
W
T
W
W
W
C
H
F
H
D
J
L
R
G
J
R
G
B
G
B
This one might be harder than the last, so I can give a hint sooner if there is enough demand.