The VagueGeometry is a PostgreSQL extension to manage vague spatial objects based on the Vague Spatial Algebra (VASA).
To cite VagueGeometry:
The paper that describes VASA is:
VagueGeometry is completely developed and maintained by Anderson Chaves Carniel.
Complete documentation at http://gbd.dc.ufscar.br/vaguegeometry/ and https://github.com/accarniel/VagueGeometry/wiki