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Heligoland Stamps
Postage Stamps and Postal History of Heligoland
Wikipedia page providing a brief overview of Heligoland stamps and postal history.
Album Pages: Heligoland
Scanned album pages from the worldwide stamp collection of Antonius Ra.
Heligoland Stamps
Fritz Wagner's detailed study of Heligoland stamps.
Heligoland Stamps
A specialized listing by Allan Olover (in PDF format).