Manual annotations that require more than one source of functional data to support the assignment of the associated GO term
The Gene Ontology Consortium uses the IC (Inferred by Curator) evidence code when an annotation cannot be supported by any direct evidence, but can be inferred by GO annotations that have been annotated to the same gene/gene product identifier in conjunction with the curator's knowledge of biology (supporting GO annotations must not be IC-evidenced). In many cases an IC-evidenced annotation simply applies the same reference that was used in the supporting GO annotation.  The use of IC evidence code in an annotation with reference GO_REF:0000036 signifies a curator inferred the GO term based on evidence from multiple sources of evidence/GO annotations. The 'with/from' field in these annotations will therefore supply more than one GO identifier, obtained from the set of supporting GO annotations assigned to the same gene/gene product identifier which cite publicly-available references.
GO Annotation working group