http://www.deltaed.com/packages/flexslider/blocks/flexslider/js/retina.js
https://www.miller-motte.edu/blocks/testimonial_slider/js/retina.js
https://www.miller-motte.edu/blocks/page_list/templates/footer_blog_list/js/retina.js
http://www.esstech.com/blocks/flexslider/js/retina.js
http://vxicorp.com/packages/flexslider/blocks/flexslider/js/retina.js
http://aiu.dk/packages/flexslider/blocks/flexslider/js/retina.js