text: * McGrew, Roderick. Encyclopedia of Medical History (1985), brief history pp 25–30
  * [http://dels.nas.edu/metagenomics Our Microbial Planet]  A free poster from the National Academy of Sciences about the positive roles of micro-organisms.
  *[https://web.archive.org/web/20080527234727/http://www.asm.org/ASM/files/ccLibraryFiles/Filename/000000003691/Uncharted_Microbial_World.pdf "Uncharted Microbial World: Microbes and Their Activities in the Environment"] Report from the American Academy of Microbiology
  * [http://dels.nas.edu/dels/rpt_briefs/metagenomics_final.pdf Understanding Our Microbial Planet: The New Science of Metagenomics]  A 20-page educational booklet providing a basic overview of metagenomics and our microbial planet.
  * [http://tolweb.org/Eukaryotes/3 Tree of Life Eukaryotes]
  * [http://www.genomenewsnetwork.org/categories/index/microbes.php Microbe News from Genome News Network]
  * [https://web.archive.org/web/20090920024442/http://gsbs.utmb.edu/microbook/toc.htm Medical Microbiology] On-line textbook
  * [http://www.microbiologytext.com/index.php?module=Book&func=toc&book_id=4 Through the microscope: A look at all things small]  On-line microbiology textbook by Timothy Paustian and Gary Roberts, University of Wisconsin-Madison