Cross sectional observational, not case control

From BugSigDB
"Cross sectional observational, not case control" is not a number.PubmedParser error: Invalid PMID, please check. (PMID: sectional observational, not case control Cross sectional observational, not case control)
Needs review
Citation
PMID PubMed identifier for scientific articles.
DOI Digital object identifier for electronic documents.
URI Uniform resource identifier for web resources.
Authors
Journal
Year