Hah, or not.. I dont think "out" would give you exposure to the name. "In" you have the most chance, mainly internet but books would work, dont think there would be many casual mentionings, like in novels. So it would need to be about a specefic subject, like africa. Or just an ecyclopedia.
Welp, i've grown to accustomed to quizzes that are a "starts with a..." topic. Stared at the answer box for about a minute before I decided to read the description.
Mentally going through all the countries I missed PNG because there isn't a W in those initials. Sigh. I'm just glad there is no W is UAE, UK, USA, or CAR.
None. That's how many I found!