1. Agterberg, F. P., “Value contours and improved regression techniques for ore reserve valuations, contributions to discussion,” J. S. African Inst. Mining Met., pp. 108-109 (1963).
2. Agterberg, F. P., “Methods of trend-surface analysis,” International Symposium on Applications of Statistics, Operation Research and Computers in the Mineral Industry, Colorado School of Mines Quart., Vol. 59, No. 4, pp. 111–130 (1964).
3. Allen, P., and Krumbein, W. C., “Secondary trend components in the top Ashdown pebble bed: A case history,” J. Geol., Vol. 70, No. 5, pp. 507–538 (1962).
4. Baird, A. K., McIntyre, D. B., and Welday, E. E., “Trend surfaces of high order (abstract),” Geol. Soc. Am., Spec. Paper 76, p. 1880 (1965).
5. Baird, A. K., McIntyre, D. B., and Welday, E. E., “Geochemical and structural studies in batholithic rocks of Southern California, Pt. II. Sampling of the Rattlesnake Mountain pluton for chemical composition, variability, and trend analysis,” Bull. Geol. Soc. Am., Vol. 78, pp. 191–222 (1967).