IIW History 1948-1958

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second with the additional material exhibited at Zurich (1955) and lVIaclrid (1956) a nd the third with documents exhibited for the first time at Essen (1957). These catalogues, to which supplements will be aclclecl to cover future exhibitions, constitute a comprehensive collection of bibliographical documents which , because they are periodically brought up to elate, are of considerable value from the point of vievv of reference. 'vVe must here pay tribute to the Secretariats of the IIW, the welding institutes of host countries a nd