public function nextVerse()
	{
		if ($this->isEmpty())
			throw new Exception(__METHOD__ . ': Can\'t find next - current passage is invalid.');
		$oLastVerse = $this->getLastVerse();

		return $this->oBible->nextVerse(
			$oLastVerse->book_id,
			$oLastVerse->chapter,
			$oLastVerse->verse
		);
	}