Here are the Robin Reich papers I was thinking of:
Czaplewski, R. L. and R. M. Reich. 1993. Expected value and variance of
Moran's bivariate spatial autocorrelation statistic under permutation.
Res. Pap. Rm-309. U. S. Department of Agriculture, Rocky Mountain Forest
and Range Experiment Station, Fort Collins, CO. 13p.
Reich, R. M., R. L. Czaplewski, and W. A. Bechtold. 1994. Spatial
cross-correlation in growth of undisturbed natural shortleaf pine stands
in northern Georgia. Journal of Environmental and Ecological Statistics.
Reich, R. M. and R. L. Czaplewski. 1995. Bivariate spatial
autocorrelation: A new technique for assessing spatial patterns. pp
91-100. In: Proc., 1993 IUFRO S4.11 Conference on Stochastic Spatial
Models in Forestry, May 18-21, 1993, Thessaloniki, Greece.