@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		CorefUnit other = (CorefUnit) obj;
		if (docRef == null) {
			if (other.docRef != null)
				return false;
		} else if (!docRef.equals(other.docRef))
			return false;
		if (sentenceNo != other.sentenceNo)
			return false;
		if (wordNo != other.wordNo)
			return false;
		return true;
	}