You can find Arnold Toynbee's books for free (read or download) on several authoritative platforms:
The Balkans: A History of Bulgaria—Serbia—Greece—Rumania—Turkey The German Terror in Belgium . knigi toinbi skachat besplatno
If you are starting your research, these are his most significant contributions: Civilization On Trial : Arnold J Toynbee - Internet Archive You can find Arnold Toynbee's books for free