Number of places
Creates a study session using concepts that only appear in # places or less
(Not yet available)
Unique to place
Creates a study session using only concepts that are unique to a particular place
(Not yet available)
Unique to continent
Creates a study session using only concepts that are unique to a particular continent
(Not yet available)
Unique to custom groups
Create your own group(s) and create a study session containing only items that are unique to one of your groups
(Not yet available)