return field.compareTo(other.field);
else if (reference == other.reference) return 0; else if (reference == null) return -1; else if (other.reference == null) return 1; else return reference.compareTo(other.reference);
	public int compareTo(AvailableLoad other) {		int cmp = reference.compareTo(other.reference);		if (cmp != 0)			return cmp;		return field.compareTo(other.field);	}