Land Problem

Sir my father bought a land of 17lessas in 2001..But the owner provide my father power of attorney so that my fathher will be able to execute sale deed after that..ghe owner was not in good health at that time..But my father died in 2009 without doing registration of our land..the owner also died in 2008..we have been living in the land since 2001..Please give me advice what I have to do for registration