The Institute of Historical Research: Military History Collections website has a wealth of resources for military researchers. They have a searchable catalogue of primary source materials available at the institute, a thesis collection and has links to other military history organisations and museums.

The London Gazette website allows you to search their catalogue of issues, searching for commissions, promotions and citations for gallantry medals that have been published since 1665. Their easy to use All Notices tool will help you discover primary sources relating to all services.