Sub Articulo 92.0
I wanna assign the equation numberings with some additional
characters, i.e. like following
--------------- equation --------------- (1a)
--------------- equation --------------- (1b)
--------------- equation --------------- (1c)
--------------- equation --------------- (1d)
some other comment.....
--------------- equation --------------- (2a)
--------------- equation --------------- (2b)
--------------- equation --------------- (2c)
I know that LaTeX give the equation number with automatically increasing.
How can I solve this problem?