Although outdated, This is one of the first monographs of the species of Vespinae of the world. This is a great historical piece for anyone wanting to see how much progress has been made in the field in the last Century.

Here is a link to a downloadable/readable copy: http://www.academia.edu/1910303/Du_Buysson_1904-1905_Monographie_des_guepes_au_Vespa_IN_FRENCH