Gibson, J., M. Holohan, et al. (1946). "Amorphous carbon." Journal of the Chemical Society (Resumed): 456-461.

X-Ray diffraction photographs of the so-called "amorphous" carbons have hitherto been interpreted as indicating that they consist of exceedingly minute turbostratic graphite crystallites: this view requires modification in the case of cokes and chars prepared at temperatures below 1200°. The nature of the organic substance, from which such carbons are prepared, is an important factor in determining their crystallographic character. It has been found possible to prepare carbons which are completely amorphous, i.e., that give no coherent diffraction of X-rays, and indications have been obtained of three-dimensional, covalent cross-linking in such carbons. The bearing of these results on the crystallographic character of cokes and chars is discussed.