Drspouse - sorry I don't know - found the same dearth when we adopted 2nd time.
A picture adoption book I love is Bye Bye Baby by Allan Ahlberg. Your toddler might enjoy it anyway and find a way in.
Italian - I recommend No Matter What but for adults not children. Ditto An Adoption Diary by Maria somebody.
Dan Hughes - good for adults but to my (heretical) mind it is only one theory as to why adopted children have the difficulties they do. It's been at times a good route to understanding my DS, but in my view the strategies haven't worked to meet his needs.
Amber somebody, Why Can't My Child Behave? is a more practically focused variation on the theme. Kim Golding I would also recommend.
Bryan Post is an interesting read - again to me, more for the understanding than for the specific strategies.
If LO is nearing school age then I wouldn't be without Louise Bomber 'what about me?' and I wouldn't let his teachers be either.
If I had to suggest just two books neither would be adoption specific, though one is specific to difficult behaviour. The Explosive Child by Ross Greene and Toddler Taming(dependent on age) by Christopher Green.
But read lots and take a view as to what works for you and your child when they are here.
Good luck! Hope that match comes through soon.