We Believe contains the creeds and confessions of the Canadian Reformed Churches.  Besides the excellent editions of these documents, you’ll also find an introduction, all the proof-texts, the historic original prefaces (rarely published), and a topical index.  Right now, until March 7, you can get 20% off the normal price by using the promo code GIANT.  You can order here.  All proceeds go to support Reformed mission work in north-eastern Brazil.