Bulgarian postcard — standard format with indexing zones — publisher unidentified

Description

Standard format Bulgarian postcard, with printed areas for the recipient's address ('Куда'), recipient ('Кому'), and sender ('Индекс предприятие связи и адрес отправителя'), as well as instructions for writing the index. The reverse side shows an example of number notation for the postal index. The card is beige paper, slightly creased and with visible folds.