Link to the special method documentation in CPython from the Cython docs.

docs/src/reference/extension_types.rst

@@ -276,8 +276,10 @@ Arithmetic Methods
 Rich Comparisons
 ================
 
-* Starting with Cython 0.27, the Python special methods ``__eq__``, ``__lt__``, etc. can be implemented.
-  In previous versions, ``__richcmp__`` was the only way to implement rich comparisons.
+* Starting with Cython 0.27, the Python
+  `special methods <https://docs.python.org/3/reference/datamodel.html#basic-customization>`_
+  ``__eq__``, ``__lt__``, etc. can be implemented.  In previous versions, ``__richcmp__`` was
+  the only way to implement rich comparisons.
 * A single special method called ``__richcmp__()`` can be used to implement all the individual
   rich compare, special method types.
 * ``__richcmp__()`` takes an integer argument, indicating which operation is to be performed

docs/src/userguide/special_methods.rst

@@ -127,9 +127,11 @@ take `self` as the first argument.
 Rich comparisons
 -----------------
 
-Starting with Cython 0.27, the Python special methods :meth:``__eq__``, :meth:``__lt__``, etc.
-can be implemented. In previous versions, :meth:``__richcmp__`` was the only way to implement
-rich comparisons. It takes an integer indicating which operation is to be performed, as follows:
+Starting with Cython 0.27, the Python
+`special methods <https://docs.python.org/3/reference/datamodel.html#basic-customization>`_
+:meth:``__eq__``, :meth:``__lt__``, etc. can be implemented.  In previous versions,
+:meth:``__richcmp__`` was the only way to implement rich comparisons.  It takes an integer
+indicating which operation is to be performed, as follows:
 
 +-----+-----+-------+
 |  <  |  0  | Py_LT |
@@ -170,6 +172,8 @@ declare different types, conversions will be performed as necessary.
 General
 ^^^^^^^
 
+https://docs.python.org/3/reference/datamodel.html#special-method-names
+
 +-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
 | Name 	                | Parameters                            | Return type | 	Description                                 |
 +=======================+=======================================+=============+=====================================================+
@@ -203,6 +207,8 @@ General
 Rich comparison operators
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 
+https://docs.python.org/3/reference/datamodel.html#basic-customization
+
 +-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
 | __richcmp__           |x, y, int op                           | object      | Rich comparison (no direct Python equivalent)       |
 +-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
@@ -222,6 +228,8 @@ Rich comparison operators
 Arithmetic operators
 ^^^^^^^^^^^^^^^^^^^^
 
+https://docs.python.org/3/reference/datamodel.html#emulating-numeric-types
+
 +-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
 | Name 	                | Parameters                            | Return type | 	Description                                 |
 +=======================+=======================================+=============+=====================================================+
@@ -267,6 +275,8 @@ Arithmetic operators
 Numeric conversions
 ^^^^^^^^^^^^^^^^^^^
 
+https://docs.python.org/3/reference/datamodel.html#emulating-numeric-types
+
 +-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
 | Name 	                | Parameters                            | Return type | 	Description                                 |
 +=======================+=======================================+=============+=====================================================+
@@ -286,6 +296,8 @@ Numeric conversions
 In-place arithmetic operators
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+https://docs.python.org/3/reference/datamodel.html#emulating-numeric-types
+
 +-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
 | Name 	                | Parameters                            | Return type | 	Description                                 |
 +=======================+=======================================+=============+=====================================================+
@@ -319,6 +331,8 @@ In-place arithmetic operators
 Sequences and mappings
 ^^^^^^^^^^^^^^^^^^^^^^
 
+https://docs.python.org/3/reference/datamodel.html#emulating-container-types
+
 +-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
 | Name 	                | Parameters                            | Return type | 	Description                                 |
 +=======================+=======================================+=============+=====================================================+
@@ -342,6 +356,8 @@ Sequences and mappings
 Iterators
 ^^^^^^^^^
 
+https://docs.python.org/3/reference/datamodel.html#emulating-container-types
+
 +-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
 | Name 	                | Parameters                            | Return type | 	Description                                 |
 +=======================+=======================================+=============+=====================================================+
@@ -377,6 +393,8 @@ Buffer interface [legacy] (no Python equivalents - see note 1)
 Descriptor objects (see note 2)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+https://docs.python.org/3/reference/datamodel.html#emulating-container-types
+
 +-----------------------+---------------------------------------+-------------+-----------------------------------------------------+
 | Name 	                | Parameters                            | Return type | 	Description                                 |
 +=======================+=======================================+=============+=====================================================+