yii2: how to creating a back link button -

i'm new in yii2 , i'm not able find button in yii2, found solution in yii1 is:

echo chtml::link('back',yii::app()->request->urlreferrer); 

but i'm not able find solution in yii2, can me?

try:

   echo \yii\helpers\html::a( 'back', yii::$app->request->referrer);