diff --git a/sql/codesystem/cs-admission-class.sql b/sql/codesystem/cs-admission-class.sql
index 07cc375..c94daf9 100644
--- a/sql/codesystem/cs-admission-class.sql
+++ b/sql/codesystem/cs-admission-class.sql
@@ -1,5 +1,5 @@
 -- Admission class CodeSystem
--- Codes will need to be mapped to match US Core Act Encounter Code - http://terminology.hl7.org/CodeSystem/v3-ActCode
+-- Codes will need to be mapped to match US Core Act Encounter Code - http://terminology.hl7.org/ValueSet/v3-ActEncounterCode
 
 DROP TABLE IF EXISTS fhir_trm.cs_admission_class;
 CREATE TABLE fhir_trm.cs_admission_class(
diff --git a/sql/codesystem/cs-admission-type.sql b/sql/codesystem/cs-admission-type.sql
index 71b8713..7f14eb0 100644
--- a/sql/codesystem/cs-admission-type.sql
+++ b/sql/codesystem/cs-admission-type.sql
@@ -1,5 +1,5 @@
 -- Admission type CodeSystem
--- Codes will need to be mapped to match US Core Encounter Type -http://hl7.org/fhir/v3/ActPriority/vs.html
+-- Codes will need to be mapped to match US Core Encounter Type -http://hl7.org/fhir/ValueSet/encounter-type
 
 DROP TABLE IF EXISTS fhir_trm.cs_admission_type;
 CREATE TABLE fhir_trm.cs_admission_type(
diff --git a/sql/codesystem/cs-chartevents-d-items.sql b/sql/codesystem/cs-chartevents-d-items.sql
index 65a2a90..3271688 100644
--- a/sql/codesystem/cs-chartevents-d-items.sql
+++ b/sql/codesystem/cs-chartevents-d-items.sql
@@ -1,5 +1,5 @@
 -- Generate unique item codes for only the chartevents
--- This is pulled from the d-items CodeSystem
+-- This is pulled from the d-items CodeSystem, map to LOINC codes http://hl7.org/fhir/valueset-observation-codes.html
 
 
 DROP TABLE IF EXISTS fhir_trm.cs_chartevents_d_items;
diff --git a/sql/codesystem/cs-d-items.sql b/sql/codesystem/cs-d-items.sql
index 67c8688..f824f07 100644
--- a/sql/codesystem/cs-d-items.sql
+++ b/sql/codesystem/cs-d-items.sql
@@ -1,5 +1,6 @@
 -- Generate codesystem for icu item codes
--- Will be referenced by chartevents, datetimeevents, and outputevents
+-- Will be referenced by procedureevents, datetimeevents, and outputevents
+-- chartevents too large, an individual codesystem created for it
 
 DROP TABLE IF EXISTS fhir_trm.cs_d_items;
 CREATE TABLE fhir_trm.cs_d_items(
@@ -11,4 +12,5 @@ INSERT INTO fhir_trm.cs_d_items
 SELECT 
     DISTINCT itemid AS code
     , label AS display
-FROM mimic_icu.d_items di 
\ No newline at end of file
+FROM mimic_icu.d_items di 
+WHERE linksto IN ('procedureevents', 'datetimeevents', 'outputevents');
diff --git a/sql/codesystem/cs-lab-fluid.sql b/sql/codesystem/cs-lab-fluid.sql
index 9c5561b..bc28328 100644
--- a/sql/codesystem/cs-lab-fluid.sql
+++ b/sql/codesystem/cs-lab-fluid.sql
@@ -1,5 +1,5 @@
 -- Lab fluid CodeSystem
--- Codes will need to be mapped to something like the Specimen type example-v2 - http://hl7.org/fhir/v2/0487/index.html
+-- Codes will need to be mapped to something like the Specimen type example-v2 - http://terminology.hl7.org/ValueSet/v2-0487
 
 DROP TABLE IF EXISTS fhir_trm.cs_lab_fluid;
 CREATE TABLE fhir_trm.cs_lab_fluid(
diff --git a/sql/codesystem/cs-medication-frequency.sql b/sql/codesystem/cs-medication-frequency.sql
index 05db017..f7e0481 100644
--- a/sql/codesystem/cs-medication-frequency.sql
+++ b/sql/codesystem/cs-medication-frequency.sql
@@ -1,4 +1,5 @@
 -- Medication Frequency CodeSystem
+-- Map the frequency values to http://hl7.org/fhir/ValueSet/timing-abbreviation
 
 DROP TABLE IF EXISTS fhir_trm.cs_medication_frequency;
 CREATE TABLE fhir_trm.cs_medication_frequency(
diff --git a/sql/codesystem/cs-observation-category.sql b/sql/codesystem/cs-observation-category.sql
index fe191f9..777b33b 100644
--- a/sql/codesystem/cs-observation-category.sql
+++ b/sql/codesystem/cs-observation-category.sql
@@ -1,4 +1,5 @@
 -- Observation Category CodeSystem
+-- Map values to http://hl7.org/fhir/valueset-observation-category.html
 
 DROP TABLE IF EXISTS fhir_trm.cs_observation_category;
 CREATE TABLE fhir_trm.cs_observation_category(
diff --git a/sql/codesystem/cs-spec-type-desc.sql b/sql/codesystem/cs-spec-type-desc.sql
index 40e28ec..cfff0c5 100644
--- a/sql/codesystem/cs-spec-type-desc.sql
+++ b/sql/codesystem/cs-spec-type-desc.sql
@@ -1,5 +1,5 @@
 -- Specimen type labs CodeSystem
--- Codes will need to be mapped to something like the Specimen type example-v2 - http://hl7.org/fhir/v2/0487/index.html
+-- Codes will need to be mapped to something like the Specimen type example-v2 - http://terminology.hl7.org/ValueSet/v2-0487
 
 DROP TABLE IF EXISTS fhir_trm.cs_spec_type_desc;
 CREATE TABLE fhir_trm.cs_spec_type_desc(