?R**^ij_kl^a_b? and you will get:
The final format is highly customizable: the vertical separation between super- and subindices, where the filling dot is placed, which character is used, and many more.
The packages listed here are free – you don’t have to pay anything to use them. However, if you have found them useful enough as to give me a little present, I would be very grateful. Just go to the following wish list at Amazon.
You might consider supporting the development of these packages with a donation, too.