Here are a few links to Articles and Features of David on the Internet
Skip Cohen University - "Go with the Flow"
Skip Cohen "Why"? Series Podcast
Video on Sirui PH-20 Gimbal Head
Here is a link to download my webinar with Tamron that was recorded on April 17, 2020. https://1drv.ms/u/s!Apz-egKT153m-FW08RJDS-z6AX7i?e=Fa6Esx