Suggest me a small 868MHz antenna

Hi,
I'm looking for a small 868Mhz antenna. I was thinking of a PIFA or BIFA design. I would prefere a PCB design. Any suggestions?

Thank you

http://www.hoperf.com/pdf/antennas%2...f-ism-an1_.pdf

This is exactely my application. Problem is that antennas in this paper are for differential outputs.
I need a single ended input antenna.