Lena: Guy, have you studied for the EU law exam?
Kim: I've been doing it for the last week
Jeff: me too, horrible
Lena: I don't understand something
Tom: ?
Lena: why are Malta and Luxembourg members of the EU, but the other European microstates are not?
Kim: hmm, a good question...
Jeff: maybe because they are even smaller? It costs a lot to be a member
Tom: They are all in some kind of unions with their bigger neighbours, which are (apart from Switzerland and Liechtenstein) members of the EU and even the Schengen Area
Kim: right, makes sense
Kim: but I read today that San Marino kept a referendum about joining the EU at some point
Kim: and they even voted "YES"
Tom: really? so what happened?
Kim: the turnout was too low, so the result was invalid
Lena: so I really don't understand why they are not members
Jeff: but they are in the EU anyway, just not officially
Lena: exactly, very strange
Tom: I found the answer! In 2012 the European Commission published a report about it
Tom: And they wrote: ""the EU institutions are currently not adapted to the accession of such small-sized countries". It's from wikipedia
Kim: great! thanks!

Briefly summarize that dialogue.
Lena, Kim, Jeff and Tom are studying for the EU law exam. Malta and Luxembourg are members of the EU. Other microstates are not. San Marino kept the referendum about joining the EU, but the result was invalid. European Commission declared the EU is not adapted to the accession of microstates.