--- requirements.txt.orig	2018-12-08 11:30:14.633258651 -0700
+++ requirements.txt	2018-12-08 11:30:51.118169972 -0700
@@ -2,5 +2,5 @@ pybtex>=0.20
 pybtex>=0.20
 pybtex-docutils>=0.2.0
 Sphinx>=2.0
-oset>=0.1.3
+orderedset>=2.0
 
--- sphinxcontrib/bibtex/cache.py.orig	2018-11-28 06:47:17.000000000 -0700
+++ sphinxcontrib/bibtex/cache.py	2018-12-08 11:30:14.633258651 -0700
@@ -24,7 +24,7 @@ except ImportError:  # pragma: no cover
 import ast
 import collections
 import copy
-from oset import oset
+from orderedset import OrderedSet
 import re
 
 
@@ -200,7 +200,7 @@ class Cache:
 
         self.bibfiles = {}
         self._bibliographies = collections.defaultdict(dict)
-        self._cited = collections.defaultdict(oset)
+        self._cited = collections.defaultdict(OrderedSet)
         self._enum_count = {}
 
     def purge(self, docname):