Liu, A. Y., M. L. Cohen, et al. (1991). "Structural properties of a three-dimensional all-sp2 phase of carbon." Physical Review B 43(8): 6742-6745.

We have studied the structural properties of a recently proposed, hypothetical, all-sp2 phase of carbon, using the first-principles pseudopotential total-energy method. Our results are compared with those of an earlier tight-binding calculation. While the two calculations yield equilibrium volumes and bond lengths that are in excellent agreement, there are discrepancies in the cohesive energy, elastic constants, and predicted stability of this phase.

http://dx.doi.org/10.1103/PhysRevB.43.6742