diff --git a/20210806111448-working_with_currencies.org b/20210806111448-working_with_currencies.org
index c9eee13..9077294 100644
--- a/20210806111448-working_with_currencies.org
+++ b/20210806111448-working_with_currencies.org
@@ -8,7 +8,7 @@
An example of converting between sub-units and base units in [[id:cda9c620-fec5-4549-b979-22fc06819d77][Python]] as defined
in [[id:bb3ab7e4-8824-4c32-bc74-e5b900d6e4d1][ISO 4217: Currency Codes]].
-#+begin_src python :exports both
+#+begin_src python :exports both :eval no-export
from decimal import Decimal
import pint
diff --git a/20231212145413-historical_data_tracking.org b/20231212145413-historical_data_tracking.org
new file mode 100644
index 0000000..9a67ce6
--- /dev/null
+++ b/20231212145413-historical_data_tracking.org
@@ -0,0 +1,9 @@
+:PROPERTIES:
+:ID: 5954632d-32f9-4586-882d-1c062309e349
+:ROAM_ALIASES: Historification
+:END:
+#+title: Historical data tracking
+
+Maintaining a record of data stored in a database.
+* Resources
+- https://www.linkedin.com/pulse/historical-data-tracking-postgresql-part-1-jaime-mart%C3%ADnez-verd%C3%BA
diff --git a/20231212145613-versioning_database_records.org b/20231212145613-versioning_database_records.org
new file mode 100644
index 0000000..1a1ee0c
--- /dev/null
+++ b/20231212145613-versioning_database_records.org
@@ -0,0 +1,8 @@
+:PROPERTIES:
+:ID: 74354f68-f0b2-4928-b851-c3971eb23eeb
+:END:
+#+title: Versioning database records
+
+A form of [[id:5954632d-32f9-4586-882d-1c062309e349][Historification]] in which previous versions of records are stored
+alongside active versions, allowing previous versions to continue to be
+referenced.
diff --git a/distributed-web-application.svg b/distributed-web-application.svg
index f407057..762855d 100644
--- a/distributed-web-application.svg
+++ b/distributed-web-application.svg
@@ -1,25 +1 @@
-
\ No newline at end of file
+
\ No newline at end of file
diff --git a/monitor-layout.png b/monitor-layout.png
index 21c56e3..49350e1 100644
Binary files a/monitor-layout.png and b/monitor-layout.png differ
diff --git a/openapi-core-exceptions.svg b/openapi-core-exceptions.svg
index d9d45b6..09bc7af 100644
--- a/openapi-core-exceptions.svg
+++ b/openapi-core-exceptions.svg
@@ -1,126 +1,126 @@
-
-