resources and further reading

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image credits:

cdc / science photo library
science source/science photo library
science photo library
dr tony brain/science photo library
istock/mrruj
istock/dr_microbe
istock/jess wealleans
thinkstock
istock/bene_a
istock/naeblys
istock/nechaev-kon
istock/dr_microbe
istock/pat138241
mihai leu/zsl
giulia/flickr/cc by-nc-nd 2.0
istock/alexraths
saskia bakker
istock/dr_microbe
michelle power
istock/craigrjd
istock/georgejason
assaf anyamba
james gathany/public domain
istock/taechit taechamanodom
istock/aunt_spray
lucy thorne
shizhao on wikimedia commons under cc by 2.5
istock/nechaev-kon
istock/k_thalhofer