Possible Clues:

• Non-fiction
• Something indisputable
• Trivia champ's tidbit
• Really, after "in"
• It's never wrong
• It's true that it sounds as if Arty might build on it
• Actually, you'll find it in this
• Actual event starts in Finland and ends in Baltic port
• This might be the whole truth - or afterwards only contributory to it
• Checker's item