diff --git a/invenio/modules/search/walkers/search_unit.py b/invenio/modules/search/walkers/search_unit.py
index e9a302a08..8bd2c9e8c 100644
--- a/invenio/modules/search/walkers/search_unit.py
+++ b/invenio/modules/search/walkers/search_unit.py
@@ -1,96 +1,102 @@
 # -*- coding: utf-8 -*-
 #
 # This file is part of Invenio.
 # Copyright (C) 2014, 2015 CERN.
 #
 # Invenio is free software; you can redistribute it and/or
 # modify it under the terms of the GNU General Public License as
 # published by the Free Software Foundation; either version 2 of the
 # License, or (at your option) any later version.
 #
 # Invenio is distributed in the hope that it will be useful, but
 # WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 # General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with Invenio; if not, write to the Free Software Foundation, Inc.,
 # 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 
 """Implement AST vistor."""
 
 from intbitset import intbitset
+
 from invenio_query_parser.ast import (
-    AndOp, KeywordOp, OrOp,
-    NotOp, Keyword, Value,
+    AndOp, DoubleQuotedValue, EmptyQuery,
+    GreaterOp, Keyword,
+    KeywordOp, NotOp, OrOp,
+    RangeOp, RegexValue,
     SingleQuotedValue,
-    DoubleQuotedValue,
-    RegexValue, RangeOp,
-    ValueQuery, EmptyQuery
+    Value, ValueQuery,
 )
 from invenio_query_parser.visitor import make_visitor
 
 from ..searchext.engines.native import search_unit
 
 
 class SearchUnit(object):
 
     """Implement visitor using ``search_unit`` API."""
 
     visitor = make_visitor()
 
     # pylint: disable=W0613,E0102
 
     @visitor(AndOp)
     def visit(self, node, left, right):
         return left & right
 
     @visitor(OrOp)
     def visit(self, node, left, right):
         return left | right
 
     @visitor(NotOp)
     def visit(self, node, op):
         return intbitset(trailing_bits=1) - op
 
     @visitor(KeywordOp)
     def visit(self, node, left, right):
         if isinstance(right, intbitset):  # second level operator
             left.update(dict(p=right))
         else:
             left.update(right)
         return search_unit(**left)
 
     @visitor(ValueQuery)
     def visit(self, node, op):
         return search_unit(**op)
 
+    @visitor(GreaterOp)
+    def visit(self, node, op):
+        op["p"] = "{0}->".format(op["p"])
+        return op
+
     @visitor(Keyword)
     def visit(self, node):
         return dict(f=node.value)
 
     @visitor(Value)
     def visit(self, node):
         return dict(p=node.value)
 
     @visitor(SingleQuotedValue)
     def visit(self, node):
         return dict(p=node.value, m='p')
 
     @visitor(DoubleQuotedValue)
     def visit(self, node):
         return dict(p=node.value, m='e')
 
     @visitor(RegexValue)
     def visit(self, node):
         return dict(p=node.value, m='r')
 
     @visitor(RangeOp)
     def visit(self, node, left, right):
         return dict(p="%s->%s" % (left, right))
 
     @visitor(EmptyQuery)
     def visit(self, node):
         return intbitset(trailing_bits=1)
 
     # pylint: enable=W0612,E0102