British national archives. 

 - London :  Her Majestry's Stationery Office HMSO) ,  1971 
 - 76p. :  ill. ;  20 cm.  
 - GP technical list  No. 24 .
<br/><br/>Includes bibliographical references. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Archives
<br/><br/><label>Gov. Doc. Class. No.: </label>GB HMSO GP SL-24