Please help to find books about orders and algebras on trees.
If there is no modern books, please advice good old ones!
I'm more interested in finite trees (my current problem), but infinite ones are very appreciated too (as probably there is no difference between fin/inf in some contexts).


I'm especially interested in the ordered group on trees.



Modern books about orders and algebras on trees
1) Trees (Springer Monographs in Mathematics) 1st ed. 1980. Corr. 2nd printing 2002 Edition by Jean-Pierre Serre


