3733953 -OEChem-02060822572D 0 0 0 0 0 0 0 0 0999 V2000 M END > 3733953 > 2 > ChemIDplus > 013981787 > 13981-78-7 Calcium, isotope of mass 53 Calcium-53 > 13981-78-7 > 013981787 > http://chem.sis.nlm.nih.gov/chemidplus/ > http://chem.sis.nlm.nih.gov/chemidplus/direct.jsp?result=advanced®no=013981787 $$$$