diff --git a/input/1802.md b/input/1802.md
index ccf0388..2a885e3 100644
--- a/input/1802.md
+++ b/input/1802.md
@@ -45,7 +45,12 @@ These materials contain lots of side digressions and alternative perspectives.
 They are not considered part of the course,
 and you should not feel obligated to read them; they're just for your interest.
 
-- `R20 11/25` [Surface](/upload/1802/r20.pdf)
+- `R23 12/09` TBD
+- `R22 12/04` TBD
+- `R21 12/02` TBD
+- Extra optional session on November 27
+- `R20 11/25` Surface and flux
+  - Evan wasn't here today, so no special notes for this session
 - `R19 11/20` [Spherical](/upload/1802/r19.pdf)
 - `R18 11/18` [Triple integral](/upload/1802/r18.pdf)
 - No special notes for November 13, review for midterm 3