Inscription
lower left in graphite: OKTP; lower right in graphite: a. Abts 09.; lower right verso in graphite by unknown hand: Abt: Untitled (12 bits) OKTP
lower left in graphite: OKTP; lower right in graphite: a. Abts 09.; lower right verso in graphite by unknown hand: Abt: Untitled (12 bits) OKTP