Long term capial gains on immovable property

1. Immovable property purchase by mother fy 1963-64. 2. Mother died in fy 2013-14. 3. Property acquired by four son as a successor with equal share. 4. Four son want to sales of immovable property during the year.5. Please gudie me calculation of long term captial gains and base year purpose of index cost of acquisition . Urgent reply required