diff --git a/latex/book/book.tex b/latex/book/book.tex
index 99b001a..92610c9 100644
--- a/latex/book/book.tex
+++ b/latex/book/book.tex
@@ -1,5 +1,5 @@
 \DocumentMetadata{testphase = {phase-II,sec,toc,graphic,minipage,float,text}}
-\documentclass{article}
+\documentclass[a4paper]{article}
 
 % Files
 \usepackage[subpreambles=true]{standalone}
diff --git a/latex/document/document.tex b/latex/document/document.tex
index a493f03..cf5a7de 100644
--- a/latex/document/document.tex
+++ b/latex/document/document.tex
@@ -1,5 +1,5 @@
 \DocumentMetadata{testphase = {phase-III,math,firstaid}}
-\documentclass{article}
+\documentclass[a4paper]{article}
 
 \usepackage[T1]{fontenc} % encoding
 \renewcommand{\familydefault}{\sfdefault} % sans-serif font