diff --git a/Specification drafting guidelines.md b/Specification drafting guidelines.md
index 953ed2104b14f030dbaf0185628d5a05261f3eab..cf6b76f94c97e21373fc3740b1c6491d08335e21 100644
--- a/Specification drafting guidelines.md	
+++ b/Specification drafting guidelines.md	
@@ -73,7 +73,7 @@ E.g.
 		|Rows        |Merged columns           |
 		+------------+-------------------------+
 		
-	> Note: Grid tables are not supported by GitLab, so they will not be rendered (Title 2 not rendered in italic)  
+	> Note: Grid tables are not supported by GitLab, so they will not be rendered (Work in progress to implement a filter for Gitlab markdown rendering)  
 		
 Text formatting (bold, italic, links), lists, multiline can be used in both pipe and grid tables.
 
@@ -94,6 +94,8 @@ Alignment can be used in both pipe and grid tables by inserting ":" in the heade
 	
 More detailed information can be found at [Pandoc documentation](https://pandoc.org/MANUAL.html#extension-grid_tables)
 
+In addition, an online converter/checker tool is available at [Grid Table converter](http://tools.etsi.org/gridtable-ie/) to facilitate the creation of grid tables.
+
 ## Diagrams
 
 Diagrams can be specified by using UML diagrams. The recommendation is to generate the PlantUML diagram image by using any PlantUML online servers ([ETSI PlantUML server](http://tools.etsi.org/plant)), and adding both the source code (.puml) and the image files to the media folder. Then, the diagram can be added as a normal figure as described at [Figures](#-figures).
@@ -131,4 +133,19 @@ More detailed information about formulas (operators, symbols, equations, ...) ca
 
 ## Notes
 
+## Symbols
+
+Symbols can be used into a markdown specification. More detail information can be found at [Markdown guide](https://www.markdownguide.org/hacks/#symbols). Here a list of most common
+symbols:
+
+1. Copyright (©) — `©`
+1. Registered trademark (®) — (`®`)
+1. Trademark (™) — (`™`)
+1. Euro (€) — (`€`)
+1. Left arrow (←) — (`←`)
+1. Up arrow (↑) — (`↑`)
+1. Right arrow (→) — (`→`)
+1. Down arrow (↓) — (`↓`)
+1. Degree (°) — (`°`)
+1. Pi (π) — (`π`)