Chase now has an easy link where you can find referral links for all of your Chase cards. You can also find the details on the referral bonus at this page as well.
Direct Link to find all referrals (login required) – toggle cards to get the link for each card
(Note, this page sometimes shows links from older, closed cards as well. Be sure to share with friends the links that are from active cards which can receive the referrer bonus.)
The other options to find referral links are to fish through your email where Chase sends them from time-to-time, or go to this catch-all page and enter the card details one at a time.
Hat tip to USCCS
Source: doctorofcredit.com