Hi gaurav
For SRM functional you would have the sap standard books you can buy the same from the link below ;
However for technical you would not have any books it would be based on more of your exp in working on the module if you know ABAP it would be pretty much the same in SRM as well so no specific Book related to SRM for that ..Incase you want to prepare for the exam SRM 7 certification then
Main books
Overview of the SAP SRM Solution
SRM210
SRM 270 SRM MDM
Additional Optional reading
SRM 300 Sourcing
DSRM71
Check all the details in the link below
