Lewis, K E, Northrop, A, Crook, G, Mather, J, Martin, J, Holt, D, Clayton, H, Roepstorff, L, Peterson, M & Hobbs, S 2015, ' Comparison of equipment used to measure shear properties in equine arena surfaces ', Biosystems Engineering, vol. 137, pp. 43-54 . https://doi.org/10.1016/j.biosystemseng.2015.07.006