LETTERLABELS is the jGraph module of jLab.

 LETTERLABELS	For automatically putting letter labels on subplots.
 
    LETTERLABELS puts letter labels '(a)','(b)','(c)' etc., on the
    subplots of the current figure, in the upper left-hand corner of
    each subplot window.
 
    LETTERLABELS(I) specifies the labelling position, clockwise from 
    top left: 
 
 		I=1	Top left
 		I=2	Top right
 		I=3	Bottom right
 		I=4	Bottom left
 
    LETTERLABELS(H,I), where H is a vector of handles to subplots,
    puts labels on the subplots indicated by H.
 
    LETTERLABELS(H,I,'d'), begins the labelling with letter 'd'.
 
    LETTERLABELS will not put the letters on the right subplots if you
    click on them before hand (because this changes the order of the
    subplot handles).  Also if you want to label the subplots in a
    nonstandard order, do this by reordering H.
    _________________________________________________________________
    This is part of JLAB --- type 'help jlab' for more information
    (C) 2000--2021 J.M. Lilly --- type 'help jlab_license' for details