Finnish Wikipedia - Season details for the Suomen Cup going back to 1955 (with some gaps).
Suomen Urheilumuseo Archive Files - Annual reports of the Suomen Palloliitto containing comprehensive results of the Finnish Cup (Suomen Cup) from 1955 to 1975.
SportsStats - Finnish Cup (Suomen Cup) results from 1999.
International Soccer Server (Archived) - Finnish Cup results for 1999, 2000, 2001, 2002 and 2003 in Riku Soininen's archived site.
Suomen Cup - Latest information on the Finnish Cup.
Bari '91 - National Cup results back to 2000.
English Wikipedia - Finnish Cup seasons for recent seasons.