Card design doubt

Im with some doubts about card design. Im using bootstrap and there is a card that has an image at top, then a title, below the title some summary and below the summary a button like a "Read more" button. My doubt is if there are some good practices or something about the summary and the "Read more" button.

My doubt is if the summary text is necessary since its usually a really small text and turns the card more long. In terms of UX there is some good practice about if this summary should exist or not? Or is not really about UX but its just a way to inform the user a little bit more about the content of the article?

Also Im with doubt about the "Read more" button, for example in the homepage if there are 8 cards and each card have the button "Read more" it doesn´t make much sense or it does? Its better dont have a button "Read more" and the whole card itself is a link?

Card with title, summary and button: http://jsfiddle.net/kzatw2r6/

Card with title and summary: http://jsfiddle.net/kzatw2r6/1/

Card with only title: http://jsfiddle.net/kzatw2r6/2/