Create three minimal XML snippet to illustrate the basics of SGML syntax

src/closeMarkup.md

+---
+header-includes:
+	- \pagestyle{empty}
+	- \usepackage{graphicx}
+	- \usepackage[left=0cm,top=0cm,right=0cm,nohead,nofoot]{geometry}
+	- \geometry{paperwidth=1.7cm, paperheight=.5cm, lmargin=-1.5cm}
+---
+
+```xml
+<author></author>
+```

src/markupPair.md

+---
+header-includes:
+	- \pagestyle{empty}
+	- \usepackage{graphicx}
+	- \usepackage[left=0cm,top=0cm,right=0cm,nohead,nofoot]{geometry}
+	- \geometry{paperwidth=2.4cm, paperheight=1.4cm}
+---
+
+```xml
+<p id="doc0">
+Contenu
+</p>
+```

src/openMarkup.md

+---
+header-includes:
+	- \pagestyle{empty}
+	- \usepackage{graphicx}
+	- \usepackage[left=0cm,top=0cm,right=0cm,nohead,nofoot]{geometry}
+	- \geometry{paperwidth=1.1cm, paperheight=.5cm, margin=0cm}
+---
+
+```xml
+<text>
+```