1. American Saciety for Testing and Materials. 1976a. ASTM D 3511–76: Standard Test Method for Pilling Resistance and Other Related Surface Changes of Textile Fabrics: Brush Pilling Tester Method.
2. American Society for Testing and Materials. 1976b. ASTM D 3312–76: Standard Test Method for Pilling Resistance and Other Related Surface Changes of Textile Fabrics: Random Tumble Pilling Tester Method.
3. Dougherty, E.R., and Giardina, C.R., 1988.Mathematical Methods for Artificial Intelligence and Autononrous Systems, Prentice-hall, Englewood Cliffs, NJ, USA.
4. Jain, A.K., 1984.Fundamentals of Digital Image Processing, Prentice-Hatt, Englewood Cliffs, NJ, USA.
5. Krebs, C.J., 1989.Ecological Methodology, Harper & Row, New York, NY, USA.