BS 06/30144683 DC IEC 60641-3-2. Specification for pressboard and presspaper for electrical purposes. Part 3-2. Sepecifications for individual materials. Sheet 2. Requirements for pressboard, types P.2.1, P.4.1, P.4.2, P.4.3, and B.6.1

standard by BSI Group, 01/12/2006