Refills for pencils, pens and pens can be found in any bookstore .
If you can't find them, you can purchase them from Amazon or another online store.
Searches in these online stores would be done by entering the keywords :
-Cross compatible pen refill
-Parker compatible pen refill
-0.5mm pencil refill
-2mm pencil refill
-2.8mm pencil refill
-5.6 mm pencil refill