On ethics:

Damien Keown,

Buddhist Ethics: A Very Short Introduction (Oxford: Oxford University Press, 2005).

An Introduction to Buddhist Ethics: Foundations, Values and Issues (Cambridge: Cambridge University Press, 2000).

H. Saddhatissa,

Buddhist Ethics: Essence of Buddhism (London: Wisdom Publications, 1987).

Roshi Philip Aitken,

The Mind of Clover: Essays in Zen Buddhist Ethics (Berkeley, CA: North Point Press, 1984).

The subject of Buddhism and war is dealt with in the following:

Brian Daizen Victoria,

Shafi da ba'a sani ba