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REFERENCES: |
    M. Simon, F. Mersch, C. Kuper, S. Mendricks, S. Wevering, J. Imbrock, E. Krätzig.
    Refractive indices of photorefractive bismuth titanate, barium-calcium titanate, bismuth germanium oxide, and lead germanate.
    <a href="https://doi.org/10.1002/1521-396X(199702)159:2<559::AID-PSSA559>3.0.CO;2-0"><i>Phys. Stat. Sol.</i> <b>159</b>, 559-562 (1997)</a>
COMMENTS: |
    Extraordinary ray (e). 21 °C.
CONDITIONS:
    temperature: 294
    direction: e
DATA:
  - type: formula 4
    wavelength_range: 0.45 0.70
    coefficients: 2.358 1.929 2 0.05780 1 0 0 0 1