00379cam a22000977a 4500008004000000082001100040245012000051260005000171300001100221700004900232180718b1952   xxu||||| |||| 00| 0 eng d  aT85x42  aRecent developments and techniques in the maintenance of standardscby National Physical Laboratory, United Kingdom  aLondonbHer Majesty's Stationery Officec1952  a100+p.  aUnited Kingdom. National Physical Laboratory