Natural plasters, earthen floors info

Hello folks I was wondering what books or websites preferably you would recommend regarding natural plasters and earthen floors. I am currently building pallet walls which we are going to start filling with light straw clay then finish with a natural plaster. Also where on earth would I find decent information on Cobb showers as I only ever see pictures of them and they look amazing but can never find a how to or basically any info on them.

Many thanks

Chris