Indefinite pronouns and the possessive case

Indefinite pronouns form the possessive by adding an apostrophe and an
‘‘s’’ after the word.

    Is this someone’s backpack?
    May I ask everyone’s help here?
    Somebody’s cell phone is ringing; please answer it in the other room.
    We would like to hear another’s opinion.
    The other’s situation is much different.

If you use the word else after anybody, nobody, or somebody, place the apostrophe
and the ‘‘s’’ after else, not after anybody, nobody, or somebody.
This is somebody else’s radio, not mine.
Your business is nobody else’s concern.