This is the CodeSystem that contains codes in both WHO ATC (http://www.whocc.no/atc) and WHO ATC (http://www.whocc.no/atc).
This code system http://hl7.org/fhir/comparison/CodeSystem/0810ecd3-570a-43d7-a673-d001af6fd6e3-3432 defines codes, but no codes are represented here