1. 3American Society for Testing Materials , Card Index File of X-Ray Diffraction Data , card No.956 . The American Society for Testing Materials, 260 S. Broad St. Philadelphia 2, Pa..
2. Crystal structure of high temperature cristobalite
3. 5American Society for Testing Materials , First Supplementary Card File of X-Ray Diffraction Data , 1945 , card No. II588 . American Society for Testing Materials, Philadelphia 2, Pa..