Lawrence, Rod (1999). The Exe: A River for Wildlife. Bradford-on-Avon. RSPB reserves: Exminster & Powderham Marshes(页面存档备份,存于互联网档案馆) Dawlish Warren Nature
Salmon's Tracts (页面存档备份,存于互联网档案馆) from Evangelical Tracts (页面存档备份,存于互联网档案馆) Rod Gow (1997) George Salmon: His Mathematical Work and Influence (页面存档备份,存于互联网档案馆)