https://www.ncbi.nlm.nih.gov/pubmed/7893848
https://www.ncbi.nlm.nih.gov/pubmed/14522011
https://www.ncbi.nlm.nih.gov/pubmed/16408408
https://www.ncbi.nlm.nih.gov/pubmed/7893848
https://www.ncbi.nlm.nih.gov/pubmed/14522011
https://www.ncbi.nlm.nih.gov/pubmed/16408408