code: public boolean setReferences (boolean references) {
  		boolean old = this.references;
  		if (references == old) return references;
  		if (old) {
  			referenceResolver.reset();
  			readObject = null;
  		}
  		this.references = references;
  		if (references && referenceResolver == null) referenceResolver = new MapReferenceResolver();
  		if (TRACE) trace("kryo", "References: " + references);
  		return !references;
  	}
docs: If true, each appearance of an object in the graph after the first is stored as an integer ordinal. This enables references
  to the same object and cyclic graphs to be serialized, but typically adds overhead of one byte per object. When set to true
  and no {@link #setReferenceResolver(ReferenceResolver) reference resolver} has been set, {@link MapReferenceResolver} is
  used. Default is false.
  @return The previous value.