These are three publications mostly used in Telangana: Osmania, Falcon and Sia. You can choose from any one of them.

If you want to prepare 15–20 years papers go for Sia. If you want to prepare 10 years papers you can use both Osmania and Falcon, both are equally good.

Buy the new editions so that you can be updated with all the important questions. Also, do not completely rely on the previous years question papers and try to learn every topic.