Here below are links to different declarations, charters, manifestos and short treatises about modern classical and traditional architecture. Please advise me of others and I will add them to this list.
2013, A Treatise on Modern Architecture by George Saumarez Smith, RIBA: http://astore.amazon.com/christinefran-20/detail/1905622503
2010, What Makes a Building Classical by Dino Marcantonio: http://blog.marcantonioarchitects.com/what-makes-a-building-classical/