不時着した円盤の謎

Data from <a href="http://ameqlist.com/sfn/norton.htm">ameqlist.com</a>. Number 1 in the publisher's Time Agent series; the series with its numbering doesn't appear on the front covers until 3 and 4. Ameqlist notes an essay by 福島正実 (Masami Fukushima) but doesn't give a title.