diff --git a/lib/nconf/provider.js b/lib/nconf/provider.js
index a67509f..b0ec3f3 100644
--- a/lib/nconf/provider.js
+++ b/lib/nconf/provider.js
@@ -24,8 +24,9 @@ var Provider = exports.Provider = function (options) {
   // Setup default options for working with `stores`,
   // `overrides`, `process.env` and `process.argv`.
   //
-  options      = options || {};
-  this.sources = [];
+  options       = options || {};
+  this._stores  = {};
+  this._sources = [];
     
   //
   // Add any stores passed in through the options
@@ -43,6 +44,19 @@ var Provider = exports.Provider = function (options) {
       self.add(store.name || name || store.type, store);
     });
   }
+  
+  //
+  // Add any read-only sources to this instance
+  //
+  if (options.source) {
+    this._sources.push(this.create(options.source.type || options.source.name, options.source));
+  }
+  else if (options.sources) {
+    Object.keys(options.sources).forEach(function (name) {
+      var source = options.sources[name];
+      self._sources.push(self.create(source.type || source.name || name, source));
+    });
+  }
 };
 
 //
@@ -86,7 +100,7 @@ Provider.prototype.use = function (name, options) {
     });
   }
   
-  var store = this.sources[name],
+  var store = this._stores[name],
       update = store && !sameOptions(store);
   
   if (!store || update) {
@@ -118,10 +132,10 @@ Provider.prototype.add = function (name, options) {
     throw new Error('Cannot add store with unknown type: ' + type);
   }
   
-  this.sources[name] = this.create(type, options);
+  this._stores[name] = this.create(type, options);
   
-  if (this.sources[name].loadSync) {
-    this.sources[name].loadSync();
+  if (this._stores[name].loadSync) {
+    this._stores[name].loadSync();
   }
   
   return this;
@@ -135,7 +149,7 @@ Provider.prototype.add = function (name, options) {
 // this was used in the call to `.add()`.
 //
 Provider.prototype.remove = function (name) {
-  delete this.sources[name];
+  delete this._stores[name];
   return this;
 };
 
@@ -171,14 +185,14 @@ Provider.prototype.get = function (key, callback) {
   // the entire set of stores, but up until there is a defined value.
   //
   var current = 0,
-      names = Object.keys(this.sources),
+      names = Object.keys(this._stores),
       self = this,
       response;
       
   async.whilst(function () {
     return typeof response === 'undefined' && current < names.length;
   }, function (next) {
-    var store = self.sources[names[current]];
+    var store = self._stores[names[current]];
     current++;
     
     if (store.get.length >= 2) {
@@ -268,7 +282,7 @@ Provider.prototype.merge = function () {
 //
 Provider.prototype.load = function (callback) {
   var self = this,
-      stores = Object.keys(this.sources).map(function (name) { return self.sources[name] });
+      stores = Object.keys(this._stores).map(function (name) { return self._stores[name] });
   
   function loadStoreSync(store) {
     if (!store.loadSync) {
@@ -317,11 +331,11 @@ Provider.prototype.load = function (callback) {
     // then do so.
     //
     if (!callback) {
-      mergeSources(loadBatch(self.sources));
+      mergeSources(loadBatch(self._sources));
       return loadBatch(stores);
     }
     
-    loadBatch(self.sources, function (err, data) {
+    loadBatch(self._sources, function (err, data) {
       if (err) {
         return callback(err);
       }
@@ -331,7 +345,7 @@ Provider.prototype.load = function (callback) {
     });
   }
   
-  return self.sources.length 
+  return self._sources.length 
     ? loadSources()
     : loadBatch(stores, callback);
 };
@@ -350,10 +364,10 @@ Provider.prototype.save = function (value, callback) {
   }
   
   var self = this,
-      names = Object.keys(this.sources);
+      names = Object.keys(this._stores);
   
   function saveStoreSync(name) {
-    var store = self.sources[name];
+    var store = self._stores[name];
     
     if (!store.saveSync) {
       throw new Error('nconf store ' + store.type + ' has no saveSync() method');
@@ -363,7 +377,7 @@ Provider.prototype.save = function (value, callback) {
   }
   
   function saveStore(name, next) {
-    var store = self.sources[name];
+    var store = self._stores[name];
     
     if (!store.save && !store.saveSync) {
       return next(new Error('nconf store ' + store.type + ' has no save() method'));
@@ -404,7 +418,7 @@ Provider.prototype._execute = function (action, syncLength /* [arguments] */) {
       response;
   
   function runAction (name, next) {
-    var store = self.sources[name];
+    var store = self._stores[name];
 
     if (destructive && store.readOnly) {
       return next();
@@ -416,15 +430,15 @@ Provider.prototype._execute = function (action, syncLength /* [arguments] */) {
   }
   
   if (callback) {
-    return async.forEach(Object.keys(this.sources), runAction, function (err) {
+    return async.forEach(Object.keys(this._stores), runAction, function (err) {
       return err ? callback(err) : callback();
     });
   }
 
 
-  Object.keys(this.sources).forEach(function (name) {
+  Object.keys(this._stores).forEach(function (name) {
     if (typeof response === 'undefined') {
-      var store = self.sources[name];
+      var store = self._stores[name];
 
       if (destructive && store.readOnly) {
         return;
diff --git a/test/fixtures/scripts/nconf-change-argv.js b/test/fixtures/scripts/nconf-change-argv.js
index 1648da2..1aaed1a 100644
--- a/test/fixtures/scripts/nconf-change-argv.js
+++ b/test/fixtures/scripts/nconf-change-argv.js
@@ -11,6 +11,6 @@ var nconf = require('../../../lib/nconf').argv();
 // Remove 'badValue', 'evenWorse' and 'OHNOEZ'
 //
 process.argv.splice(3, 3);
-nconf.sources['argv'].loadArgv();
+nconf._stores['argv'].loadArgv();
 process.stdout.write(nconf.get('something'));
 
diff --git a/test/nconf-test.js b/test/nconf-test.js
index 482a543..2cb8a39 100644
--- a/test/nconf-test.js
+++ b/test/nconf-test.js
@@ -28,7 +28,7 @@ vows.describe('nconf').addBatch({
     "the use() method": {
       "should instaniate the correct store": function () {
         nconf.use('memory');
-        assert.instanceOf(nconf.sources['memory'], nconf.stores.Memory);
+        assert.instanceOf(nconf._stores['memory'], nconf.stores.Memory);
       }
     },
     "it should": {
diff --git a/test/provider-test.js b/test/provider-test.js
index 4b592cb..f2440da 100644
--- a/test/provider-test.js
+++ b/test/provider-test.js
@@ -24,13 +24,13 @@ vows.describe('nconf/provider').addBatch({
       "calling the use() method with the same store type and different options": {
         topic: new nconf.Provider().use('file', { file: files[0] }),
         "should use a new instance of the store type": function (provider) {
-          var old = provider.sources['file'];
+          var old = provider._stores['file'];
 
-          assert.equal(provider.sources.file.file, files[0]);
+          assert.equal(provider._stores.file.file, files[0]);
           provider.use('file', { file: files[1] });
 
-          assert.notStrictEqual(old, provider.sources.file);
-          assert.equal(provider.sources.file.file, files[1]);
+          assert.notStrictEqual(old, provider._stores.file);
+          assert.equal(provider._stores.file.file, files[1]);
         }
       },
       "when 'argv' is true": helpers.assertSystemConf({
@@ -71,7 +71,7 @@ vows.describe('nconf/provider').addBatch({
         "should have the result merged in": function (provider) {
           provider.load();
           provider.merge(override);
-          helpers.assertMerged(null, provider.sources.file.store);
+          helpers.assertMerged(null, provider._stores.file.store);
         }
       }
     }