https://www.dropbox.com/s/10vpo9x6d8vgjzy/acdl%20siena%2019%20lecture%201.pptx?dl=0
https://www.dropbox.com/s/108f7byjp3an11l/acdl%20siena%2019%20lecture%202%20NEW.pptx?dl=0
https://www.dropbox.com/s/h2aeqtkz2cbz8te/acdl%20siena%2019%20lecture%203%20NEWER.pptx?dl=0