Readers are no longer scheduled in the K, 1, 2, and 1+2 Core Instructor's Guides. Instead the Readers are scheduled in the Reader/Study Guide supplement and also in the corresponding Language Arts IG.
Readers for Cores 3 through 6/Alt 6 are still scheduled in both the Core IG and the LA IG.
Readers for Core 7 are scheduled in the Core 7 IG only.
Literature (called "Readers" in the catalog) in Core 100 are scheduled in the Core 100 IG only.
Literature in Cores 200 and above are scheduled in the Core IG only.