I've posted an update in another thread here. I don't have a reference, but it was posted today in answer to a question from Tom Kershaw about learning electronics.

I'm working on it Bill. Please be patient. I am not a fast writer and have had to do weeks of vAg experiments in the lab in order to complete one chapter. I am waiting for pump tubing at the present time for the next set of experiments. The last batch was not the right type and the correct type is still on order.

See the other post for more information.

PE