Thomas,
Scott is correct and you have misjudged the book in question. In short, you are wrong in your overall view of the book and its source material.
The book's title is Napoleon's Grande Armee of 1813; therefore, it is about the French-not the Austrians, Russians, or Prussians. It is then common sense to conclude that the greater majority of the sources used for the book would be French. If a book is being researched and written on Napoleon's Grande Armee shouldn't the resource material be French? I would think so.
The overwhelming majority of the source material is either archival or primary and the memoirs of Parquin, Lejeune, Marmont, Rapp, Savary, Barres, as well as Napoleon's and Davout's correspondence have been used in the preparation of the volume. Further, Six has been used as well as Foucart, Lynn, and the Esposito/Elting Atlas, all of which are excellent secondary source material. The endnotes are full of period correspondence also.
Your criticism of the book is quite puzzling, to me anyways.
Sincerely,
Kevin