diff --git a/cpl/cplusplus.md b/cpl/cplusplus.md
index 0783076..d4b41bf 100644
--- a/cpl/cplusplus.md
+++ b/cpl/cplusplus.md
@@ -1,5 +1,9 @@
 # Cplusplus
 
+- [C++ Core Guidelines](http://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines)
+    - [The C++ Core Guidelines are a collaborative effort led by Bjarne Stroustrup, much like the C++ language itself. They are the result of many person-years of discussion and design across a number of organizations.](https://github.com/isocpp/CppCoreGuidelines)
+    - [The Guidelines Support Library (GSL) contains functions and types that are suggested for use by the C++ Core Guidelines maintained by the Standard C++ Foundation. This repo contains Microsoft's implementation of GSL.](https://github.com/Microsoft/GSL)
+
 ## TMP(template metaprogramming)
 
 C++ allows template metaprogramming (TMP), a technique in which so-called templates are used by a compiler to generate temporary source code that is merged with the rest of the source code and then compiled
\ No newline at end of file
diff --git a/index/standard.md b/index/standard.md
index c416b19..f62a0ae 100644
--- a/index/standard.md
+++ b/index/standard.md
@@ -21,6 +21,10 @@
 - [Computer Graphics Matrix](../cg/cgMatrix.md)
 - [vk spec](https://registry.khronos.org/vulkan/specs/1.2/pdf/vkspec.pdf)
 
+### [gl](https://registry.khronos.org/OpenGL/specs/gl/)
+- [GLSLangSpec.4.40](https://registry.khronos.org/OpenGL/specs/gl/GLSLangSpec.4.40.pdf)
+- [glspec4.6](https://registry.khronos.org/OpenGL/specs/gl/glspec46.core.pdf)
+
 ## Images
 
 - [图像格式](../others/images.md)
diff --git a/math/pbr3ed.html b/math/pbr3ed.html
index 291146f..a4abd54 100644
--- a/math/pbr3ed.html
+++ b/math/pbr3ed.html
@@ -11,14 +11,10 @@
         <h1>content</h1>
         <div class="d-flex flex-column">
             <ol>
-                <li><a href="#section1">projection matrix</a></li>
                 <li><a href="#section5">Color And Radiometry</a></li>
+                <li><a href="#section7">Samping and Reconstruction</a></li>
             </ol>
         </div>
-        <div>
-            <h4 id="section1">projection matrix</h4>
-            <p>22</p>
-        </div>
         <div>
             <h4 id="section5">5. Color And Radiometry</h4>
             <p>可见光的波段380到780，400以下是bluish， 550是greens，大于650是reds</p>
@@ -46,10 +42,10 @@ <h5>5.4 Radiometry辐射度学</h5>
             </div>
         </div>
         <div>
-            <h4 id="section5">7. Samping and Reconstruction</h4>
+            <h4 id="section7">7. Samping and Reconstruction</h4>
             <div>
-                <h5>5.2.1 XYZ Color</h5>
-                <p>A remarkable property of the human visual system makes it possible to represent colors for human perception with just three floating-point numbers. The tristimulus theory of color perception says that all visible SPDs can be accurately represented for human observers with three values, \( \mathcal{x}_{\lambda} \), , \( \mathcal{y}_{\lambda} \) and \( \mathcal{z}_{\lambda} \). Given an emissive SPD , these values are computed by integrating its product with the spectral matching curves \(X(\lambda)\), \(Y(\lambda)\), and \(Z(\lambda)\): </p>
+                <h5></h5>
+                <p></p>
             </div>
             <div>
                 <h5>7.2.1 Evaluating Samping Patterns: Discrepancy</h5>