Suzaku and XMM-Newton observations of the North Polar Spur: Charge exchange or ISM absorption? Liyi Gu, Junjie Mao, Elisa Costantini and Jelle Kaastra A&A, 594 (2016) A78 Published online: 14 October 2016 DOI: 10.1051/0004-6361/201628609