Sources on the Development of the Socialist International (1907-1919), Friedrich Ebert Stiftung
This collection of digital sources contains the 23 volumes of the Histoire de la Deuxième Internationale, 1889-1914, published by Édition Minkoff, consisting of publications by the congresses of the International between 1888 and 1917. Available in German, French and English.
The Laws of War, The Avalon Project, Yale Law School
This primary source database presents the Hague Conventions of 1899 and 1907, Geneva Conventions and Miscellaneous Treaties, Conventions and Agreements.