diff --git a/AUTHORS b/AUTHORS
index 70ca409..66dcc22 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -10,3 +10,4 @@ Simon Sapin
 Stefan Behnel
 Thomas Grainger
 Varialus
+Arthur Darcet
diff --git a/cssselect/parser.py b/cssselect/parser.py
index 9bb039c..1aed6f8 100644
--- a/cssselect/parser.py
+++ b/cssselect/parser.py
@@ -76,7 +76,7 @@ def __init__(self, tree, pseudo_element=None):
         #: +-------------------------+----------------+--------------------------------+
         #: | Invalid pseudo-class    | ``li:marker``  | ``None``                       |
         #: +-------------------------+----------------+--------------------------------+
-        #: | Functinal               | ``a::foo(2)``  | ``FunctionalPseudoElement(…)`` |
+        #: | Functional              | ``a::foo(2)``  | ``FunctionalPseudoElement(…)`` |
         #: +-------------------------+----------------+--------------------------------+
         #:
         #: .. _Lists3: http://www.w3.org/TR/2011/WD-css3-lists-20110524/#marker-pseudoelement
@@ -92,6 +92,20 @@ def __repr__(self):
         return '%s[%r%s]' % (
             self.__class__.__name__, self.parsed_tree, pseudo_element)
 
+    def canonical(self):
+        """Return a CSS representation for this selector (a string)
+        """
+        if isinstance(self.pseudo_element, FunctionalPseudoElement):
+            pseudo_element = '::%s' % self.pseudo_element.canonical()
+        elif self.pseudo_element:
+            pseudo_element = '::%s' % self.pseudo_element
+        else:
+            pseudo_element = ''
+        res = '%s%s' % (self.parsed_tree.canonical(), pseudo_element)
+        if len(res) > 1:
+            res = res.lstrip('*')
+        return res
+
     def specificity(self):
         """Return the specificity_ of this selector as a tuple of 3 integers.
 
@@ -116,6 +130,9 @@ def __repr__(self):
         return '%s[%r.%s]' % (
             self.__class__.__name__, self.selector, self.class_name)
 
+    def canonical(self):
+        return '%s.%s' % (self.selector.canonical(), self.class_name)
+
     def specificity(self):
         a, b, c = self.selector.specificity()
         b += 1
@@ -151,6 +168,10 @@ def __repr__(self):
     def argument_types(self):
         return [token.type for token in self.arguments]
 
+    def canonical(self):
+        args = ''.join(token.css() for token in self.arguments)
+        return '%s(%s)' % (self.name, args)
+
     def specificity(self):
         a, b, c = self.selector.specificity()
         b += 1
@@ -174,6 +195,10 @@ def __repr__(self):
     def argument_types(self):
         return [token.type for token in self.arguments]
 
+    def canonical(self):
+        args = ''.join(token.css() for token in self.arguments)
+        return '%s:%s(%s)' % (self.selector.canonical(), self.name, args)
+
     def specificity(self):
         a, b, c = self.selector.specificity()
         b += 1
@@ -192,6 +217,9 @@ def __repr__(self):
         return '%s[%r:%s]' % (
             self.__class__.__name__, self.selector, self.ident)
 
+    def canonical(self):
+        return '%s:%s' % (self.selector.canonical(), self.ident)
+
     def specificity(self):
         a, b, c = self.selector.specificity()
         b += 1
@@ -210,6 +238,12 @@ def __repr__(self):
         return '%s[%r:not(%r)]' % (
             self.__class__.__name__, self.selector, self.subselector)
 
+    def canonical(self):
+        subsel = self.subselector.canonical()
+        if len(subsel) > 1:
+            subsel = subsel.lstrip('*')
+        return '%s:not(%s)' % (self.selector.canonical(), subsel)
+
     def specificity(self):
         a1, b1, c1 = self.selector.specificity()
         a2, b2, c2 = self.subselector.specificity()
@@ -238,7 +272,20 @@ def __repr__(self):
         else:
             return '%s[%r[%s %s %r]]' % (
                 self.__class__.__name__, self.selector, attrib,
-                self.operator, self.value)
+                self.operator, self.value.value)
+
+    def canonical(self):
+        if self.namespace:
+            attrib = '%s|%s' % (self.namespace, self.attrib)
+        else:
+            attrib = self.attrib
+
+        if self.operator == 'exists':
+            op = attrib
+        else:
+            op = '%s%s%s' % (attrib, self.operator, self.value.css())
+
+        return '%s[%s]' % (self.selector.canonical(), op)
 
     def specificity(self):
         a, b, c = self.selector.specificity()
@@ -258,10 +305,13 @@ def __init__(self, namespace=None, element=None):
         self.element = element
 
     def __repr__(self):
+        return '%s[%s]' % (self.__class__.__name__, self.canonical())
+
+    def canonical(self):
         element = self.element or '*'
         if self.namespace:
             element = '%s|%s' % (self.namespace, element)
-        return '%s[%s]' % (self.__class__.__name__, element)
+        return element
 
     def specificity(self):
         if self.element:
@@ -282,6 +332,9 @@ def __repr__(self):
         return '%s[%r#%s]' % (
             self.__class__.__name__, self.selector, self.id)
 
+    def canonical(self):
+        return '%s#%s' % (self.selector.canonical(), self.id)
+
     def specificity(self):
         a, b, c = self.selector.specificity()
         a += 1
@@ -303,6 +356,13 @@ def __repr__(self):
         return '%s[%r %s %r]' % (
             self.__class__.__name__, self.selector, comb, self.subselector)
 
+    def canonical(self):
+        subsel = self.subselector.canonical()
+        if len(subsel) > 1:
+            subsel = subsel.lstrip('*')
+        return '%s %s %s' % (
+            self.selector.canonical(), self.combinator, subsel)
+
     def specificity(self):
         a1, b1, c1 = self.selector.specificity()
         a2, b2, c2 = self.subselector.specificity()
@@ -536,7 +596,7 @@ def parse_attrib(selector, stream):
     if next != ('DELIM', ']'):
         raise SelectorSyntaxError(
             "Expected ']', got %s" % (next,))
-    return Attrib(selector, namespace, attrib, op, value.value)
+    return Attrib(selector, namespace, attrib, op, value)
 
 
 def parse_series(tokens):
@@ -591,6 +651,12 @@ def is_delim(self, *values):
     type = property(operator.itemgetter(0))
     value = property(operator.itemgetter(1))
 
+    def css(self):
+        if self.type == 'STRING':
+            return repr(self.value)
+        else:
+            return self.value
+
 
 class EOFToken(Token):
     def __new__(cls, pos):
diff --git a/cssselect/xpath.py b/cssselect/xpath.py
index 22cd029..ad2ccbd 100644
--- a/cssselect/xpath.py
+++ b/cssselect/xpath.py
@@ -308,10 +308,12 @@ def xpath_attrib(self, selector):
             attrib = '@' + name
         else:
             attrib = 'attribute::*[name() = %s]' % self.xpath_literal(name)
-        if self.lower_case_attribute_values:
-            value = selector.value.lower()
+        if selector.value is None:
+            value = None
+        elif self.lower_case_attribute_values:
+            value = selector.value.value.lower()
         else:
-            value = selector.value
+            value = selector.value.value
         return method(self.xpath(selector.selector), attrib, value)
 
     def xpath_class(self, class_selector):
diff --git a/tests/test_cssselect.py b/tests/test_cssselect.py
index f01aa7f..0819f25 100644
--- a/tests/test_cssselect.py
+++ b/tests/test_cssselect.py
@@ -244,6 +244,39 @@ def specificity(css):
         assert specificity('#lorem + foo#ipsum:first-child > bar:first-line'
             ) == (2, 1, 3)
 
+    def test_css_export(self):
+        def css2css(css, res=None):
+            selectors = parse(css)
+            assert len(selectors) == 1
+            assert selectors[0].canonical() == (res or css)
+
+        css2css('*')
+        css2css(' foo', 'foo')
+        css2css('Foo', 'Foo')
+        css2css(':empty ', ':empty')
+        css2css(':before', '::before')
+        css2css(':beFOre', '::before')
+        css2css('*:before', '::before')
+        css2css(':nth-child(2)')
+        css2css('.bar')
+        css2css('[baz]')
+        css2css('[baz="4"]', "[baz='4']")
+        css2css('[baz^="4"]', "[baz^='4']")
+        css2css("[ns|attr='4']")
+        css2css('#lipsum')
+        css2css(':not(*)')
+        css2css(':not(foo)')
+        css2css(':not(*.foo)', ':not(.foo)')
+        css2css(':not(*[foo])', ':not([foo])')
+        css2css(':not(:empty)')
+        css2css(':not(#foo)')
+        css2css('foo:empty')
+        css2css('foo::before')
+        css2css('foo:empty::before')
+        css2css('::name(arg + "val" - 3)', "::name(arg+'val'-3)")
+        css2css('#lorem + foo#ipsum:first-child > bar::first-line')
+        css2css('foo > *')
+
     def test_parse_errors(self):
         def get_error(css):
             try: