File:Gustav Frederik Lassen gravsten.jpg - Wikimedia Commons
Gustav Lassen Holding ApS, Charlottenlund | firma | degulesider.dk
arkiv.dk | Lassen, Gustav Frederik
Gustav Heidemann Lassen, Svenstrup J | person | krak.dk
Lassen the spy'. A Russian, described by the author as an espionage swindler. After a failed attempt to gain money in return secrets he did not have, Lassen was captured by Steinhauer