00615cas|a2200169 i 450000500170000000800410001703500150005810000180007324500930009126000750018430000130025949000380027265000180031070000180032870000200034681000790036620260817161441.0011199s1976    enk u m rtt  00|  a1eng d  a.b100525251 aNelson, P. M.10aAcoustic performance of the M6 noise barriers /cby ..., P. G. Abbott and A. C. Salvidge  aCrowthorne, Berkshire :bTransport and Road Research Laboratory,c1976  a11, 5 p.1 aTRRL Laboratory report ;vno. 731 0aTraffic noise10aAbbott, P. G.10aSalvidge, A. C.2 aTransport and Road Research Laboratory.tTRRL Laboratory report ;vno. 731