Ruth van Reken has devoted a lot of her work to Third Culture Kids and has written a book about them, given talks, written papers, etc. She is a second generation Third Culture Kid herself.
Who are Third Culture Kids?
The following definition of a certain group of people has been occupying my mind for the last couple of months (and even before then): THIRD CULTURE KID (TCK).
The first time I heard about this group was, when I was asked to participate in a PhD research as interviewee - fitting the description of TCK myself.
Third culture kids (TCK) are individuals who are (or were as children) raised in a culture other than their parents' or the culture of their country of nationality, and live in such an environment during a significant part of their early development years. They typically are exposed to a greater volume and variety of cultural influences than those who grow up in one particular cultural setting.  The term applies to both adults and children, as the term "kid" refers to an individual's formative or developmental years. However, for clarification, sometimes the term adult third culture kid (ATCK) is used. (Wikipedia)
Third Culture Kid is a relatively recently pinpointed term for the above described individual, but finds a lot of resonance among like-minded people sharing these experiences.
Academic research is also focusing more on this topic in recent decades, as more global citizens evolve from the world wide movements ...
This magazine will bundle relevant content for those who want to know more about Third Culture Kid, who they are, where you can find them, what defines them, etc.
Most of the content shared here is in English, part of it in Dutch...
For an elaboration on these two groups of individuals I can truly recommend the following source.
The Third Culture Model
@Model designed by Ruth E. Van Reken 1987
Common characteristics of Third Culture experience (for adults as well as kids)