@techreport{anne1973a,
  title = {A survey on the occurrence of epiterranean soil algae in Singapore island}
  author = {Anne Johnson},
  url = {https://www.nparks.gov.sg/sbg/research/publications/gardens-bulletin-singapore/-/media/sbg/gardens-bulletin/4-4-26-2-12-y1973-v26p2-gbs-pg-289.pdf},
  year = {1973}
}