1. La grosseur des grains des matières pulvérulentes;Feret;Assoc. Int. pour l'Essai des Mat.,1931
2. Calculation of the specific surface of powder;Heywood;Proc. Inst. Mech. Engrs,1933
3. Processing pictorial information with digital computers;Kirsch;Trans. Am. Inst. Elec. Engrs, CP,1957