From e33704212181a4401e35071b103b6ef7f788493f Mon Sep 17 00:00:00 2001
From: Eric Prestat <eric.prestat@gmail.com>
Date: Wed, 18 Sep 2024 14:42:04 +0100
Subject: [PATCH] Mention source of `elements` database in docstring

---
 doc/reference/material.rst | 76 ++++++++++++++++++++++++--------------
 exspy/_misc/elements.py    | 20 ++++++++++
 2 files changed, 68 insertions(+), 28 deletions(-)

diff --git a/doc/reference/material.rst b/doc/reference/material.rst
index 1df8d98c0..b4fd6b99b 100644
--- a/doc/reference/material.rst
+++ b/doc/reference/material.rst
@@ -18,7 +18,9 @@
 .. autoattribute:: exspy.material.elements
    :annotation:
 
-Database of element properties. The following properties are included:
+Database of element properties.
+
+The following properties are included:
 
 .. code::
 
@@ -32,32 +34,50 @@ Database of element properties. The following properties are included:
     └── Physical_properties
         └── density_gcm3
 
-Examples:
+The X-ray lines energies are taken from Chantler et al. [1]_.
 
-.. code::
+The line weight, more precisely the approximate line weight for K,L M
+shells are taken from Electron Probe Quantitation (EPQ) library [2]_.
+
+The field ``threshold`` and ``edge`` are taken from Gatan EELS atlas
+https://eels.info/atlas, as retrieved in June 2020.
+
+Examples
+
+>>> exspy.material.elements.Fe.General_properties
+├── Z = 26
+├── atomic_weight = 55.845
+└── name = iron
+>>> exspy.material.elements.Fe.Physical_properties
+└── density (g/cm^3) = 7.874
+>>> exspy.material.elements.Fe.Atomic_properties.Xray_lines
+├── Ka
+│   ├── energy (keV) = 6.404
+│   └── weight = 1.0
+├── Kb
+│   ├── energy (keV) = 7.0568
+│   └── weight = 0.1272
+├── La
+│   ├── energy (keV) = 0.705
+│   └── weight = 1.0
+├── Lb3
+│   ├── energy (keV) = 0.792
+│   └── weight = 0.02448
+├── Ll
+│   ├── energy (keV) = 0.615
+│   └── weight = 0.3086
+└── Ln
+    ├── energy (keV) = 0.62799
+    └── weight = 0.12525
+
+    
+References
+
+.. [1] Chantler, C.T., Olsen, K., Dragoset, R.A., Kishore, A.R.,
+   Kotochigova, S.A., and Zucker, D.S. (2005), X-Ray Form Factor,
+   Attenuation and Scattering Tables (version 2.1).
+   https://dx.doi.org/10.18434/T4HS32
 
-    >>> exspy.material.elements.Fe.General_properties
-    ├── Z = 26
-    ├── atomic_weight = 55.845
-    └── name = iron
-    >>> exspy.material.elements.Fe.Physical_properties
-    └── density (g/cm^3) = 7.874
-    >>> exspy.material.elements.Fe.Atomic_properties.Xray_lines
-    ├── Ka
-    │   ├── energy (keV) = 6.404
-    │   └── weight = 1.0
-    ├── Kb
-    │   ├── energy (keV) = 7.0568
-    │   └── weight = 0.1272
-    ├── La
-    │   ├── energy (keV) = 0.705
-    │   └── weight = 1.0
-    ├── Lb3
-    │   ├── energy (keV) = 0.792
-    │   └── weight = 0.02448
-    ├── Ll
-    │   ├── energy (keV) = 0.615
-    │   └── weight = 0.3086
-    └── Ln
-        ├── energy (keV) = 0.62799
-        └── weight = 0.12525
+.. [2] Ritchie, N. EPQ is the Electron Probe Quantification library
+   - the basis for DTSA-II.
+   https://github.com/usnistgov/EPQ
diff --git a/exspy/_misc/elements.py b/exspy/_misc/elements.py
index ba7153143..115b7a65d 100644
--- a/exspy/_misc/elements.py
+++ b/exspy/_misc/elements.py
@@ -4996,6 +4996,14 @@
     └── Physical_properties
         └── density_gcm3
 
+The X-ray lines energies are taken from Chantler et al. [1]_.
+
+The line weight, more precisely the approximate line weight for K,L M
+shells are taken from Electron Probe Quantitation (EPQ) library [2]_.
+
+The field ``threshold`` and ``edge`` are taken from Gatan EELS atlas
+https://eels.info/atlas, as retrieved in June 2020.
+
 Examples
 --------
 >>> exspy.material.elements.Fe.General_properties
@@ -5023,6 +5031,18 @@
 └── Ln
     ├── energy (keV) = 0.62799
     └── weight = 0.12525
+
+    
+References
+----------
+.. [1] Chantler, C.T., Olsen, K., Dragoset, R.A., Kishore, A.R.,
+   Kotochigova, S.A., and Zucker, D.S. (2005), X-Ray Form Factor,
+   Attenuation and Scattering Tables (version 2.1).
+   https://dx.doi.org/10.18434/T4HS32
+
+.. [2] Ritchie, N. EPQ is the Electron Probe Quantification library
+   - the basis for DTSA-II.
+   https://github.com/usnistgov/EPQ
 """
 
 # read dictionary of atomic numbers from eXSpy, and add the elements that