References

RArṇ, 1, 24.2
  teṣāṃ vinaṣṭabuddhīnāṃ rasajñānaṃ sudurlabham //Context
RArṇ, 1, 46.1
  rasavidyā parā vidyā trailokye 'pi sudurlabhā /Context
RArṇ, 1, 57.2
  rasārṇavaṃ mahātantramidaṃ paramadurlabham //Context
RArṇ, 12, 242.0
  tasya mantraṃ pravakṣyāmi triṣu lokeṣu durlabham //Context