6ISO 4427 - 1996 Polyethylene ( PE ) pipes for water supplySpecifications [ S ]. 1996.
7ISO 4437 - 1997 Buried Polyethylene(PE) pipes for the supply of gaseous fuels-Metric series-Specifications [ S ]. 1997.
8ISO 9080 -2003 Plastics piping and ducting systems-Determination of the long-term hydrostatic strength of thermoplastics materials in pipe form by extrapolation [ S ]. 2003.
