File:Russia 1992 No 19 stamp (1st standard issue of Russia. 4th issue. Saint Isaac's Cathedral (architect Auguste de Montferrand), Saint Petersburg) 2.png - Wikimedia Commons
China stamp 1899 Russian Post Offices SG4 5k purple used
Postage stamps and postal history of Russia - Wikipedia
Stamps from Russia, Soviet Union - Freestampcatalogue.com - The free online stampcatalogue with over 500.000 stamps listed.