/** References to two different molecules. * Available for any reference to molecules but * normally will be the normal reference attribute on the join element. * The order of molecules is preserved and may matter. * @return String[] */ public String[] getMoleculeRefs2() { StringArraySTAttribute att = (StringArraySTAttribute) this.getMoleculeRefs2Attribute(); if (att == null) { return null; } return att.getStringArray(); } /** References to two different molecules.