A video that Thusness and I found to be very good.
https://www.youtube.com/watch?v=0xc3XdOiGGI&feature=share
https://www.youtube.com/watch?v=0xc3XdOiGGI&feature=share
An article I posted to Syl Via, reposting as a separate topic as I thought it might be of benefit and useful pointers to others. Reflection...