http://www.servicecanada.gc.ca/eng/sc/sin/
http://www.servicecanada.gc.ca/eng/sin/apply/proof.shtml
Permanent residents
You must submit
ONE of the following primary documents:
Permanent Resident Card issued by Citizenship and Immigration Canada. This is the only acceptable document if your claim was processed in Canada.
Confirmation of Permanent Residence AND visa counterfoil affixed to a foreign passport or a travel document
Confirmation of Permanent Residence AND foreign passport for visa exempt countries
Record of Landing issued before June 28, 2002.
Verification of landing. This document is provided when an original of the Record of Landing or the Confirmation of Permanent Residence is not available (i.e. lost, misplaced, etc.).