43. R.P. Gardner and K. Sukanjnajtee, “A Combined Tracer and BackCalculation Method for Determining Particulate Breakage Functions in Ball Milling. Part I. Rationale and Description of the Proposed Method”, Powder Technology, 6, pp. 6574 (1972). 
44. R.M. Moreira, J.O.N.M. DeCastro, and R.P. Gardner, “A Combined Tracer and BackCalculation Method for Determining Particulate Breakage Functions in Ball Milling, Part II. Application to Hematite Iron Ore in a Batch Laboratory Mill”, Powder Technology, 6, pp. 7583 (1972).

50. R. P. Gardner and K. Sukanjnajtee, “A Combined Tracer and Backcalculation Method for Determining Particulate Breakage Functions in Ball Milling. Part III. Simulation of an OpenCircuit Continuous Milling System”, Powder Technology, 7, pp. 169l79 (1973). 
56. R.P. Gardner, “Use of the TanksinSeries Transport Model with Segregated Flow Transient Models for Continuous, OpenCycle Ball Milling”, Transactions of the Society of Mining Engineers of AIME, 256, pp. 227229 (1974). 
60. R.P. Gardner, “Evaluation of a Radioisotope Tracer Method for Determination of Simulation Parameters in OpenCircuit Continuous Ball Mills”, Transactions of the Society of Mining Engineers of AIME, 258, pp. 4654 (1975). 
64. R.P. Gardner and L.G. Austin, “The Applicability of the First Order Grinding Law to Particles Having a Distribution of Strengths”, Powder Technology, 12, pp. 6569 (1975). 
86. R.P. Gardner, K. Verghese, and R.S.C. Rogers, “The OnStream Determination of Large Scale Ball Mill Residence Time Distributions with ShortLived Radioactive Tracers”, Mining Engineering, April, 1980, pp. 42243l.

106. D.W. Wall and R.P. Gardner, “A Monte Carlo Simulation of the Rate of Breakage in Ball Mills”, Proceedings of Powder and Bulk Solids Conference, Chicago, Illinois, May 1315, 1980, 4 pages.

108. R.P. Gardner, R.S.C. Rogers, and K. Verghese, “Development and Use of a ShortLived Radioactive Tracer Method for Applying the Mechanistic Approach to Industrial, Continuous Ball Mills”, Proceedings of the Fifth European Symposium on Comminution, June 35, 1980, Amsterdam, The Netherlands, pp. 621639.

133. Robin P. Gardner and Kuruvilla Verghese, “A Review of the Mathematical Approaches to Nonlinear Grinding and a Suggested General Treatment for Environmental Nonlinearities Based on the Use of Influence Functions”, Particulate Science and Technology, An International Journal, Vol. 2, No. 2, 101120 (1984). 