diff --git a/Cargo.toml b/Cargo.toml
index aa4153a..87b4431 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,7 +2,7 @@
 name = "asciimath-rs"
 description = "AsciiMath parser"
 repository = "https://github.com/trivernis/asciimath-rs"
-version = "0.5.2"
+version = "0.5.3"
 authors = ["trivernis <trivernis@protonmail.com>"]
 edition = "2018"
 readme = "README.md"
diff --git a/src/format/mathml.rs b/src/format/mathml.rs
index 3a5815c..1a8222b 100644
--- a/src/format/mathml.rs
+++ b/src/format/mathml.rs
@@ -373,7 +373,7 @@ impl ToMathML for Group {
     fn to_mathml(&self) -> String {
         match self {
             Group::Vector(v) => v.to_mathml(),
-            Group::MSep => ",".to_string(),
+            Group::MSep => "<mo>,</mo>".to_string(),
             Group::Parentheses(p) => p.to_mathml(),
             Group::Brackets(b) => b.to_mathml(),
             Group::Braces(b) => b.to_mathml(),
diff --git a/src/lib.rs b/src/lib.rs
index bb9853a..a59be21 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -40,7 +40,7 @@ pub fn parse(content: String) -> Expression {
 
 #[cfg(test)]
 mod tests {
-    use crate::elements::group::{Brackets, Group, Matrix, Vector};
+    use crate::elements::group::{Brackets, Group, Matrix, Parentheses, Vector};
     use crate::elements::literal::{Literal, Number};
     use crate::elements::special::{Expression, Special, Sum};
     use crate::elements::Element;
@@ -311,7 +311,7 @@ mod tests {
     #[test]
     fn it_parses_vectors() {
         assert_eq!(
-            parse("((1), (2)) - f".to_string()),
+            parse("((1), (2))(1,2) - f".to_string()),
             Expression {
                 children: vec![
                     Element::Group(Group::Vector(Vector {
@@ -328,6 +328,20 @@ mod tests {
                             }]
                         ]
                     })),
+                    Element::Group(Group::Parentheses(Parentheses {
+                        inner: Expression {
+                            children: vec![
+                                Element::Literal(Literal::Number(Number {
+                                    number: "1".to_string()
+                                })),
+                                Element::Group(Group::MSep),
+                                Element::Literal(Literal::Number(Number {
+                                    number: "2".to_string()
+                                }))
+                            ]
+                        }
+                        .boxed()
+                    })),
                     Element::Literal(Literal::Operation(Operation::Minus)),
                     Element::Literal(Literal::Function(Function::F))
                 ]