Does license statement be included in each project file?

[Chiara Marmo <chiara.marmo@u-psud.fr>]

Hello,

I'm packaging the Aravis library[1] to include it in debian-astro blend.
The license is clearly identified in the COPYING[2] file, but in some files (Makefiles for example, or XML metadata, and some .h files) license is not included in the header. 
There is one file[3] with explicit 'custom' license (compatible, I think, with debian policies).

To avoid misunderstanding, does the license statement be included in each project file?

Thanks for any help!
Bests,
Chiara

[1] https://github.com/AravisProject/aravis
[2] https://github.com/AravisProject/aravis/blob/master/COPYING
[3] https://github.com/AravisProject/aravis/blob/master/src/arvrealtime.c

-- 
Chiara Marmo
Ingénieur de Recherche GEOPS - Paris Sud-11
Bât 509
Tel: +33 (0)1 69 15 49 03