Robin HIgham 
Guide to the Sources of British Military History [PDF ebook] 

Designed to fill an overlooked gap, this book, originally published in 1972, provides a single unified introduction to bibliographical sources of British military history. Moreover it includes guidance in a number of fields in which no similar source is available at all, giving information on how to obtain acess to special collections and private archives, and links military history, especially during peacetime, with the development of science and technology.