1. https://www.ncbi.nlm.nih.gov/pubmed/19120014
  2. https://www.ncbi.nlm.nih.gov/pubmed/19159610 Review
  3. https://www.ncbi.nlm.nih.gov/pubmed/20367601
  4. https://www.ncbi.nlm.nih.gov/pubmed/21454507
  5. https://www.ncbi.nlm.nih.gov/pubmed/23026390
  6. https://www.ncbi.nlm.nih.gov/pubmed/23092317
  7. https://www.ncbi.nlm.nih.gov/pubmed/24460971
  8. https://www.ncbi.nlm.nih.gov/pubmed/29738689