4. Adding Items - Issue with props vs refs

[trivopr]

Hi Ray,
I get a problem in Section 4. Adding Items.
When i click: toggleAptDisplay and code below

	toggleAptDisplay() {
		this.props.handleToggle();
	}

	handleAdd(e) {
		let objItem = {
			petName: this.refs.inputPetName.value,
			ownerName: this.refs.inputOwnerName.value,
			aptDate: this.refs.inputAptDate.value + ' ' + this.refs.inputAptTime.value,
			aptNotes: this.refs.inputAptNotes.value		
		} // objItem

		e.preventDefault();
		this.props.addApt(objItem);
	} // handleAdd

Console log is : Uncaught TypeError: Cannot read property 'props' of null(…)
The above problem on Refs is the same. Help me plz,
Thanks.