Citation: Kwei, G.H.; Cheong, S.-W.; von Dreele, R.B.; Thompson, J.D.; Fisk, Z. (1990). Structure of T*-phase superconductors: Anomalous x-ray-diffraction study of cation ordering in La0.9 Gd0.9 Sr0.2 Cu O4. Physical Review, Serie 3. B - Condensed Matter (18,1978-), 41, pp. 1889-1893.