Methods to measure potential spatial access to delivery care in low- and middle-income countries: a case study in rural Ghana - Nesbitt, Robin C.; Gabrysch, Sabine; Laub, Alexandra; Soremekun, Seyi; Manu, Alexander; Kirkwood, Betty R.; Amenga-Etego, Seeba; Wiru, Kenneth; Höfle, Bernhard; Grundy, Chris (International journal of health geographics, 2014)