Apache is a free and open-source cross-platform web server software.
Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
cdnjs is a free distributed JS library delivery service.
Google Hosted Libraries is a stable, reliable, high-speed, globally available content distribution network for the most popular, open-source JavaScript libraries.
jQuery UI is a collection of GUI widgets, animated visual effects, and themes implemented with jQuery, Cascading Style Sheets, and HTML.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Open Journal Systems (OJS) is an open-source software application for managing and publishing scholarly journals.
PayPal is an online payments system that supports online money transfers and serves as an electronic alternative to traditional paper methods like checks and money orders.
PHP is a general-purpose scripting language used for web development.
Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.