For my class, I am looking for a visual representation of the historical development of the Old Indo Aryan language:

from OIA to Vedic (Sanskrit) to Classical Sanskrit and Middle Indo Aryan languages (Prakrits), with the approximate time for each stage.
It would be especially appreciated if the map reflected the fact that some Prakrits in some respects directly continue the features 

of the Vedic language, which are lost in Classical Sanskrit.

If there exists such a map, I would be most grateful if someone explained where I can consult it.

Kind regards,

Gleb Sharygin, Dr.des.
LMU München