Article on Overt Defense here.

The Siemens-Schuckert D.IV; Best Fighter of the First World War?
When it comes to aircraft of great potential, those of the First World War are often overlooked. And while the dogfights between aircraft like the Sopwith Camel, the Fokker Dr.1 triplane and the SPAD XIII are often the source for historical recollection, this tends to...