U.S. Government UFO Report (Catalogue):

“Summary of Sightings of Unknown Phenomena,
17th District OSI” (Selected Cases)

(Air Force Office of Special Investigations, 
U.S. Air Force, Washington, D.C.)
(NICAP.org)

Quote from NICAP.org’s “1949 UFO Chronology and the Grudge Report” (nicap.org):
“This chronology is currently a 29-page report and a very important year in UFOlogy.  I want to thank all the members of the A-Team who made this possible.  To look at and/or print all the 1949 Blue Book monthly summaries, click here. Otherwise the monthly listings are inserted within this chronology by month. Note: There are 209 entries in the 38-page La Paz catalog, the ‘Summary of Sightings of Unknown Phenomena, 17th District OSI’.  But in the 1949 group there were 144 sightings and the only ones listed here are the reports with some important details to make them extraordinary. Also, brief case descriptions giving the category number, name of witness, and source in brackets (M=military), are NICAP UFO Evidence entries that haven't been located. Finally, I want thank Loren Gross for thoughtfully and diligently collecting data many years ago for his UFO Histories and supplemental notes, in particular here the year 1949. And a big thanks to CUFOS and Mary Castnor for housing them on the CUFOS site.”

The Air Force Office of Special Investigations presents UFO sighting reports from 1943 through early 1950:

http://www.nicap.org/lapazcat/AFOSI_LaPazCatalograwdata.pdf

Wikipedia article: “U.S. Air Force Office of Special Investigations”:

http://en.wikipedia.org/wiki/U.S._Air_Force_Office_of_Special_Investigations

Wikipedia article: “Lincoln LaPaz”:

https://en.wikipedia.org/wiki/Lincoln_LaPaz

The emblem of the Air Force Office of Special Investigations (AFOSI) (wikimedia.org image)

U.S. Government UFO Report:

“SPECIAL REPORT NO. 14: ANALYSIS OF

REPORTS OF UNIDENTIFIED AERIAL OBJECTS,

PROJECT NO. 10073, 5 MAY 1955”

(U.S. Air Force, Washington, D.C.)

The PDF was produced by The Project Blue Book Archive, with the generous support of PROJECT 1947, The Sign Historical Group and the Archives for UFO Research, News and Information Service, NICAP.org informs:

http://www.nicap.org/docs/pbbsr/BBA-PBSR14.pdf

(ufocasebook.com image)

U.S. Government Journal UFO Article:

“OPERATIONS & TRAINING; UFO'S SERIOUS BUSINESS”

The Inspector General (TIG) Brief, Number 26,

Volume XI, 24 December 1959

(U.S. Air Force, Washington, D.C.)

Source: NICAP.org

The Inspector General Brief reports on Air Force Regulation 
200-2 (AFR 200-2):

http://www.nicap.org/directives/UFOS-SeriousBusiness.pdf

(U.S. Air Force/NICAP.org image)

U.S. Government Journal UFO Article:

“UNIDENTIFIED FLYING OBJECTS (UFOs)”

The Inspector General (TIG) Brief, 
Number 21, Volume XVIII, 14 October 1966

(U.S. Air Force, Washington, D.C.)

Source: CUFON.org, U.S.A.

The Inspector General Brief reports on Air Force Regulation 
80-17 (AFR 80-17, 19 September 1966):

http://www.cufon.org/cufon/tig_brief4.htm

(cufon.org image)