Agricultural land registration

Hello

Can we buy agricultural land from members of family of  a deceased person,

Land is in Andhra Pradesh and still all documentation (Pattadar passbook) is on their Fathers name (Passed away)

What is the correct procedure to follow , Deceased persons Widow and children willing to sign and transfer the land

Do we require to transfer land to deceased person's legal heir's name first or is tehre a procedure to transfer to third party directly

Thanking you