message Database
 {
  subject subjects = 0
 }
message Diagnosis
 {
  condition isAbout = 0
  string source = 0
 }
message Document
 {
  string isAbout = 0
 }
message Process
 {
  string hasInput = 0
  string hasOutput = 0
 }
message Sampling
 {
  string hasInput = 0
  string hasOutput = 0
 }
message Specimen
 {
  researchSubject hasSource = 0
  specimen hasParentSpecimen = 0
 }
message Subject
 {
  string taxon = 0
  string birthDate = 0
 }
