I am most familiar with the intervention along the Siberian Railway this comprised a brigade of British and Canadians, French troops mainly from their colonies in Indo-China, Americans and over 100, 000 Japanese. The reason for this particular intervention was two fold firstly like the other interventions to secure the military stores sent to support the Czarist government in fighting the Germans and secondly to allow the egress of the Czech Legion from Russia. There is a book by Roy MacLaren on the subject from the Canadian viewpoint (this was the first time that a major unit that included British soldiers was commanded by a Canadian general). There is an article on this intervention particularly from the US involvement in Military History Quarterly.
There are also articles in Military History Quarterly about the US involvement in the operations in and around both Murmansk and Archangel. I'm not really sure if the US was particularly involved in the operations in the south, which from what I've read consisted mainly of air support for White Russian forces. Some of the techniques developed for the rapid movement of these air units, including their ground support elements, were quite revolutionary at the time.
The fourth area of operations of interventionist forces, namely the Baltic States, is something that I know almost nothing about even though it has been written about fairly extensively. If you look around the forum you may be able to find some useful information on the subject. The only title that comes to mind is Cowan's War.
' Strip war of the mantle of its glories and excitement, and it will disclose a gibbering ghost of pain , grief, dissappointment and despair'