Dielectric functions: 
       
       
  --> Schrödinger materials     
       
1) static:

    * Thomas-Fermi
    * RPA longitudinal 2D + magnetic field
    * RPA longitudinal 1D, 2D, 3D
    
2) dynamic:

    * Vlasov longitudinal 3D
    * VFP longitudinal 3D + relaxation time
    * RPA longitudinal 1D, 2D, 3D
    * RPA longitudinal 3D + temperature
    * RPA longitudinal 2D + magnetic field
    * plasmon pole longitudinal 1D, 2D, 3D
    * Nevanlinna
    * mean spherical longitudinal 3D
    * Mermin longitudinal 3D + temperature
    * Klimontovich-Kraeft longitudinal 3D (non degenerate/highly degenerate)
    * hydrodynamic longitudinal 3D + relaxation time
    * Hu-O'Connell 1D, 2D, 3D + diffusion coefficient
    * Hartree-Fock longitudinal 3D
    * Hertel-Appel longitudinal 3D
    * Arista-Brandt longitudinal 3D + temperature (Dandrea-Ashcroft-Carlsson par.)
    * Boltzmann longitudinal 3D
    * Boltzmann longitudinal 3D+ relaxation time
    * Boltzmann transverse 3D+ relaxation time
    
    Waiting to be coded:
    * Atwal-Ashcroft 3D
    * Utsumi-Ichimaru longitudinal 3D
    * Kleinman longitudinal 3D
    
    
  --> Dirac materials