At the link below are PDF versions of a JOTI/JOTA participant certificate that includes a contact log section for recording the stations that were contacted during your event. Download and print as many as you need.
JOTI

JOTI Contact Log for Scouting America Scouts and Leaders
Click on the document (above) to view and download
JOTA

JOTA Full Page Contact Log
Click Document Title to View/Download

JOTA Quarter Page Contact Logs
Click Document Title to View/Download