Blake, Eric (September 20, 2017). Hurricane Maria Tropical Cyclone Update (Laporan). Miami, Florida: National Hurricane Center. Diakses tanggal September 20, 2017.
Staff writer (May 9, 1973). "'73, Hurricanes to be Graded". Associated Press. Diarsipkan dari versi asli tanggal May 19, 2016. Diakses tanggal December 8, 2007.
Tropical Cyclone Weather Services Program (June 1, 2006). "Tropical cyclone definitions"(PDF). National Weather Service. Diakses tanggal November 30, 2006.
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Staff writer (May 9, 1973). "'73, Hurricanes to be Graded". Associated Press. Diarsipkan dari versi asli tanggal May 19, 2016. Diakses tanggal December 8, 2007.