TY - JOUR TI - Sir Halford J. Mackinder: The Heartland theory then and now JF - Journal of Strategic Studies AU - Sloan, Geoffrey DO - 10.1080/01402399908437752 PY - 1999-06 EP - 38 SP - 15 SN - 0140-2390 SN - 1743-937X IS - 2-3 VL - 22 ER -