Author: ROUSSEV IVAN
Immediately after the Crimean War, in 1856, the "Russian company for shipping and commerce" in the Black Sea was created, which had offices in Burgas and Varna. The company supported postal services with Russia. 
 Минчев, Д. Н. За пощенско-филателното дело във Варна през XIX в. – Известия на Народния музей – Варна, Т. VIII, 1972, с. 133–151.