Properly integrate non-AngularJS libraries in your AngularJS application

Javascript_Angular_loading_nonAngular_dependencies.js

function LodashFactory($window) {  
  if(!$window._){
    // If lodash is not available you can now provide a
    // mock service, try to load it from somewhere else,
    // redirect the user to a dedicated error page, ...
  }
  return $window._;
}

// Define dependencies
LodashFactory.$inject = ['$window'];

// Register factory
yourModule.factory('_', LodashFactory);  

Where do i need to include de script tag reference to the library??