diff --git a/cyclonedx/model/definition.py b/cyclonedx/model/definition.py
index cb01568e..9d9562e8 100644
--- a/cyclonedx/model/definition.py
+++ b/cyclonedx/model/definition.py
@@ -93,6 +93,9 @@ def __str__(self) -> str:
 class Requirement:
     """
     A requirement comprising a standard.
+
+    .. note::
+        See the CycloneDX Schema for hashType: https://cyclonedx.org/docs/1.6/json/#definitions_standards_items_requirements
     """
 
     def __init__(
@@ -286,6 +289,9 @@ def __repr__(self) -> str:
 class Level:
     """
     Level of compliance for a standard.
+
+    .. note::
+        See the CycloneDX Schema for hashType: https://cyclonedx.org/docs/1.6/json/#definitions_standards_items_levels
     """
 
     def __init__(
@@ -402,6 +408,9 @@ class Standard:
     """
     A standard of regulations, industry or organizational-specific standards, maturity models, best practices,
     or any other requirements.
+
+    .. note::
+        See the CycloneDX Schema for hashType: https://cyclonedx.org/docs/1.6/xml/#type_standard
     """
 
     def __init__(
diff --git a/cyclonedx/model/lifecycle.py b/cyclonedx/model/lifecycle.py
index e6aed27b..081aeb3a 100644
--- a/cyclonedx/model/lifecycle.py
+++ b/cyclonedx/model/lifecycle.py
@@ -64,7 +64,8 @@ class PredefinedLifecycle:
     Object that defines pre-defined phases in the product lifecycle.
 
     .. note::
-        See the CycloneDX Schema definition: https://cyclonedx.org/docs/1.6/xml/#metadata_lifecycles
+        See the CycloneDX Schema definition:
+        https://cyclonedx.org/docs/1.6/json/#tab-pane_metadata_lifecycles_items_oneOf_i0
     """
 
     def __init__(self, phase: LifecyclePhase) -> None:
@@ -103,7 +104,8 @@ class NamedLifecycle:
     Object that defines custom state in the product lifecycle.
 
     .. note::
-        See the CycloneDX Schema definition: https://cyclonedx.org/docs/1.6/xml/#metadata_lifecycles
+        See the CycloneDX Schema definition:
+        https://cyclonedx.org/docs/1.6/json/#tab-pane_metadata_lifecycles_items_oneOf_i1
     """
 
     def __init__(self, name: str, *, description: Optional[str] = None) -> None: