World maps of F2 critical frequencies and maximum usable frequency factors
Subtitle: Donald H. Zacharisen
Contributors: United States. National Bureau of Standards
Series: National Bureau of Standards technical note -- 2; NBS technical note -- 2.
Publisher: National Bureau of Standards, United States Department of Commerce, Office of Technical Services
Published: 1959
Place of publication: Washington, D.C
Language: eng
Number of pages: 244
Subjects: Ionospheric radio wave propagation; Charts, diagrams; F region
Notes: Title from title screen (viewed Mar. 5, 2014).

"April 1959."

"Prepared in response to Study Program 60 and Recommendation 176 of the International Radio Consultative Committee (CCIR)."

Includes bibliographical references (page 10).