1. Shields J. Adhesives handbook. London: Butterworth, 1976. p. 1.
2. Chalmers L, Bathe P. Chemical specialties domestic and industrial. II. London: George Godwin Ltd, 1979. p. 77.
3. Heinrich H, Westfalia Separator, A. G. 18th March, 1981. p. 15.
4. Schoch TG. Cereal chemistry. London: Longmans Ltd, 1941. p. 1.
5. BS 188: Measurement of viscosity of liquids, 1957.