If you pull again when the ground is moist, it should come right up. I pulled everything in this spot in about 3 hours, about 2 yrs ago. A slow, steady force can bring up huge chunks at once, mostly all connected just under the leaves, then chase down the spots where some pieces broke coming out of the ground & pull those crowns/roots too. I've seen maybe 10 little sprigs since, soon after pulling, from pieces that didn't come all the way up. After finishing pulling those last few, haven't seen any since.

Same spot last month:

If you decide to smother, cardboard is so much easier to work with than newspaper (just remove any tape or staples.) If using newspaper, I'd use a little thicker layers, like 8-12 sheets, overlap well. If a twig pokes a hole, the Vinca will find it.