Peru Philatelic Study Circle
Chuck Wooster:
The Post Offices of Peru - (December 2016 version)  - MS Excel file, a
MUST for the postmarks collector, this file lists over 2,500 POs, when
they opened, category, location, etc. etc.  Years worth of research are
available from this single file.

Royal Philatelic Society of London:
2011.440 – Pacific Steam Navigation Company intaglio plate, ½oz,
Peru, 1857. The Museum of Philatelic History at The Royal Philatelic
Society London.
2011.441 – Pacific Steam Navigation Company intaglio plate, 1oz,
Peru, 1857. The Museum of Philatelic History at The Royal Philatelic
Society London

Wim De Gelder:
Los Resellos de Triangulos de Peru (1883-1897) - Charla AMIFIL
2017, Lima 23 de septiembre del 2017, Wim De Gelder
APS Affiliate Member # 258
Original Research Contributions