Land dispute

I am only daughter to my father aged about 70 years. My father purchased a land in the year 1950,area of 7.645 acres out of 15.29 acres . In the year 1960 my father and his brother has agreed to give some part land without mentioning any area simply saying the names of boundaries on a white paper moreover they have not approached registration or any legal document. Again my father has paid amount for sub-division of land with the neighboring land holders. After sub-division my father has got 4.79 acres(letter-2) and his brother got 3 acres (letter-1) and remaining 7.5 acres (letter-3) to neighboring person in the above land of 15.29 acres. In this sub-division process the revenue officials had made mistakes regarding the calculation of area in all three letters. As per the sketch of the land the 3 letters have following area which differs from original area(letter-1 has got 3.29 acres,letter-2 has got 4 acres,letter-3 has got 8 acres). My father was expired in the year 1964 writing registered WILL document in my name for entire property.Now this 4.79(letter-2) was gifted by me to my daughter. With the shortfall in the land area she has approached Revenue Divisional Officer and R.D.O has appointed a officer to rectify the sub-division errata and finally he measured the land and recognized the fault in the land area and again he fixed boundaries as per record. The neighboring person holding 8 acres area has accepted to the rectified boundaries. But my father brother's sons not accepting the rectified boundaries for 3 acres and they are saying that we will get equal share in the land with your father. Now the dispute is between my daughter and my father brother's sons. They are not coming for revised sub division. My question is: 1.Only writing on the white paper and sub-division will give total rights to the father brother's son. 2.Can I have any provision to get complete land as per registered document if I go legally.