Cannot read property 'get_current' of undefined

I am using this code:

"use strict"
var BasicJSOM = window.BasicJSOM || {};
BasicJSOM.Crud = BasicJSOM.Crud || {};

$(function() {
   BasicJSOM.Crud.MainDemo = new BasicJSOM.Crud.Main();
SP.SOD.executeOrDelayUntilScriptLoaded(BasicJSOM.Crud.MainDemo.readListItems("pages"), "SP.js");   
  });


 BasicJSOM.Crud.Main= function(){

    function _readListItems(library){

       var context = SP.ClientContext.get_current();
       var targetList = context.get_web().get_lists().getByTitle(library);
       var query = new SP.CamelQuery();
        var listItems = targetList.getItems();

        results = context.loadQuery(listItems);
        context.executeQueryAsync(_onSucceed, _Fail);

       function _onSucceed(){
            alert("Success"); 

       }

       function _Fail(){
       alert("fail"); 
       }

    }//end of read list


    return {
readListItems: _readListItems    
    }

 } 

But the error am having is about the SP.js is not loaded, I am using jQuery to wait for page load, then using SP.SOD.executeOrDelayUntilScriptLoaded. What else am I missing?