There is nothing called Adsense referrals. I think you are talking about referral ads. THose are high paying ads in which you can select what ads to display and you are paid only if the visitor performs some prerequisite tasks after clicking the ads.
There are google's own adsense referals where you can get paid to promote there stuff ie. Adwords/Firefox etc, you get paid everytime someone signs up/ downloads from your ad.These work well generally and you can claim firefox is great, and users should download it to enjoy your site more. Secondly google also now have referals on other stuff, ranging from magazine subscriptions to kids toys, these tend to pay more than Google's own ads, but usually require the user to buy something - opposed to downloading something for free from goog.These ad's can be used to great effect if you have a strong niche and there are referral advertising programs to you From experience i have found it is best to use a combination of both, however i had a fairly general site, if you have a good niche you could make some great $$$ by using referrals more.