diff --git a/metadata/entries/Relational_Disjoint_Set_Forests.toml b/metadata/entries/Relational_Disjoint_Set_Forests.toml
--- a/metadata/entries/Relational_Disjoint_Set_Forests.toml
+++ b/metadata/entries/Relational_Disjoint_Set_Forests.toml
@@ -1,33 +1,36 @@
 title = "Relational Disjoint-Set Forests"
 date = 2020-08-26
 topics = [
   "Computer science/Data structures",
 ]
 abstract = """
 We give a simple relation-algebraic semantics of read and write
 operations on associative arrays. The array operations seamlessly
 integrate with assignments in the Hoare-logic library. Using relation
 algebras and Kleene algebras we verify the correctness of an
 array-based implementation of disjoint-set forests with a naive union
 operation and a find operation with path compression."""
 license = "bsd"
 note = ""
 
 [authors]
 
 [authors.guttmann]
 homepage = "guttmann_homepage"
 
 [contributors]
 
 [notify]
 guttmann = "guttmann_email"
 
 [history]
 2021-06-19 = """
 added path halving, path splitting, relational Peano structures, union by rank
 (revision 98c7aa03457d)"""
+2023-08-10 = """
+added matrix model of Peano structures and order-embedding from nat
+(revision 9933c1ff260f)"""
 
 [extra]
 
 [related]