Title: Phosphate Deposits in Northern Alaska
Subtitle: Exploration of Naval Petroleum Reserve no. 4 and Adjacent Areas, Northern Alaska, 1944-53. Part 4, Regioeserve no. 4 and Adjacent Areas, Northern Alaska,  1944-539 Part 4, Regioeserve no. 4 and Adjacent Areas, Northern Alaska, 1944-53. Part 4, Regional Studies.