Before revision: Even within Mensa itself, a SIG (special interest group, an informal sub-group of Mensans sharing a particular common interest) has existed for Densa ; which, like all Mensa SIGs, required Mensa membership for admission, while it was active.
After revision: Even within Mensa itself, a SIG (special interest group, an informal sub-group of Mensans sharing a particular common interest) has existed for Densa , which, like all Mensa SIGs, required Mensa membership for admission, while it was active.