vales

https://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:6437
http://www.genome.jp/dbget-bin/www_bget?drug:D00709
http://www.genome.jp/dbget-bin/www_bget?cpd:C07841
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5284583
https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=46508406
https://www.chemspider.com/Chemical-Structure.4447633.html
http://www.bindingdb.org/bind/chemsearch/marvin/MolStructure.jsp?monomerid=50422542
https://mor.nlm.nih.gov/RxNav/search?searchBy=RXCUI&searchTerm=114477
https://www.ebi.ac.uk/chebi/searchId.do?chebiId=6437
https://www.ebi.ac.uk/chembldb/index.php/compound/inspect/CHEMBL1286
https://zinc.docking.org/substances/ZINC000001547851
http://bidd.nus.edu.sg/group/cjttd/ZFTTDDRUG.asp?ID=DAP000502
http://www.pharmgkb.org/drug/PA450206
http://www.rxlist.com/cgi/generic3/keppra.htm
https://www.drugs.com/cdi/levetiracetam.html
http://www.pdrhealth.com/drug_info/rxdrugprofiles/drugs/kep1561.shtml
https://en.wikipedia.org/wiki/Levetiracetam