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Quiring, S. M; Papakryiakou, T. N. (2003). "An evaluation of agricultural drought indices for the Canadian prairies". Agricultural and Forest Meteorology. 118 (1–2): 49–62. Bibcode:2003AgFM..118...49Q. doi:10.1016/S0168-1923(03)00072-8.
Quiring, S. M; Papakryiakou, T. N. (2003). "An evaluation of agricultural drought indices for the Canadian prairies". Agricultural and Forest Meteorology. 118 (1–2): 49–62. Bibcode:2003AgFM..118...49Q. doi:10.1016/S0168-1923(03)00072-8.
Quiring, S. M; Papakryiakou, T. N. (2003). "An evaluation of agricultural drought indices for the Canadian prairies". Agricultural and Forest Meteorology. 118 (1–2): 49–62. Bibcode:2003AgFM..118...49Q. doi:10.1016/S0168-1923(03)00072-8.
Quiring, S. M; Papakryiakou, T. N. (2003). "An evaluation of agricultural drought indices for the Canadian prairies". Agricultural and Forest Meteorology. 118 (1–2): 49–62. Bibcode:2003AgFM..118...49Q. doi:10.1016/S0168-1923(03)00072-8.
internationalboundarycommission.org
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"Wide open spaces, but for how long?". The Royal Canadian Geographical Society. The Royal Canadian Geographical Society. 16 October 2014. Archived from the original on 3 April 2016.