Adding Custom Meta Boxes to the WordPress Admin Interface

http://www.sitepoint.com/adding-custom-meta-boxes-to-wordpress/

How to Use the WordPress Custom Logo API

http://www.sitepoint.com/wordpress-custom-logo-api/?utm_medium=email&utm_campaign=SitePoint%20Front-end%20Newsletter%20%20April%2021%202016&utm_content=SitePoint%20Front-end%20Newsletter%20%20April%2021%202016+CID_65be6a19e553cf9fbceafee9b9e90fcf&utm_source=CampaignMonitor%20SitePoint&utm_term=How%20to%20Use%20the%20WordPress%20Custom%20Logo%20API

Create your first iphone app - Beginners

http://www.thegeekstuff.com/2016/03/create-iphone-app/

Google Maps API for drawing polygons

https://developers.google.com/maps/documentation/javascript/examples/polygon-simple

Create WordPress Plugins with OOP Techniques

http://code.tutsplus.com/articles/create-wordpress-plugins-with-oop-techniques--net-20153

Google Maps APIs for Multiple Locations

https://www.taniarascia.com/google-maps-apis-for-multiple-locations/
http://wrightshq.com/playground/placing-multiple-markers-on-a-google-map-using-api-3/

Executing php inside a WordPress widget without any plugin

http://www.emanueleferonato.com/2011/04/11/executing-php-inside-a-wordpress-widget-without-any-plugin/