That link was working before, I tested it.
Did another google search and found another link to the same article. Easier to read at this site too.
Katyn Massacre: An Assessment....... In case you can't read the link, allow me to give you his Source Documents. After all, you've asked for "Documents". Here you go.
Documents
Cowper, Steve. Governor of Alaska. "Executive Proclamation: A Day to
Remember Katyn" [30 April 1988]. Juneau AK: 1 April 1988.
Great Britain. War Office. "Vilnyus-Minsk." 1:1,000,000 map on one
sheet. np: Survey Production Centre, Royal Engineers, 1954.
Khatyn. Minsk: B'elarus, 1982.
U.S. Congress. Congressional Record. Washington DC: Government
Printing Office, 1943.
U.S. Congress. House of Representatives, Committee on Un-American
Activities. Lest We Forget! A Pictorial Summary of Communism in
Action: Albania, Bulgaria, Estonia, Finland, Hungary, Latvia,
Lithuania, Poland, Czechoslovakia, Rumania, Ukraine, Soviet Union.
Washington DC: U.S. Government Printing Office, 1960.
U.S. Congress. House of Representatives, Select Committee on the Katyn
Forest Massacre. The Katyn Forest Massacre: Hearings before the
Select Committee to Conduct an Investigation of the Facts,
Evidence and Circumstances of the Katyn Forest Massacre, 82d
Congress, 1st and 2d Session, 1951-1952. 7 parts. Washington DC:
U.S. Government Printing Office, 1952.
U.S. Congress. House of Representatives, Select Committee on the Katyn
Forest Massacre. The Katyn Forest Massacre: Hearings before the
Select Committee to Conduct an Investigation of the Facts,
Evidence and Circumstances of the Katyn Forest Massacre, Final
Report, 82d Congress, 2d Session, 1952. 7 parts. Washington DC:
U.S. Government Printing Office, 1952.
U. S. Department of State. Foreign Relations of the United States,
1943, Volume III, Diplomatic Papers. Washington DC: U.S.
Government Printing Office, 1963.
Newspaper and Wire Service Articles
"American Polish Leaders Brand Russia a Nation of Liars and Old
Conspirators." Chicago Tribune, 28 April 1943, 19.
Associated Press. "U.S. Report Says Airmen Taken to Soviet Union."
Springfield State Journal-Register (IL), 28 September 1993, 2.
Binyon, Michael. "Katyn Veteran Tells of Secret Police Murders." Times
(London), 7 October 1991, 8.
Bohlen, Celestine. "Russian Files Show Stalin Ordered Massacre of
20,000 Poles in 1940." New York Times, 15 October 1992, 1.
"British Try to Patch up Polish-Red Rukus." Macomb Daily Journal, 29
April 1943, 1.
Burns, John F. "Soviet Union Irked by Nordic Visitors: Some in an
Antinuclear Group Boycott Rally over Link to World War II
Massacre." New York Times, 1 August 1982, 4.
Clendenning, P.M. "Glasnost and the New Soviet History of World War II:
`Blank Spots' To Be Revealed." The Soviet Observer, 16-29
February 1988.
Coatney, Louis R. "My Turn: Sunday, April 24th: A Day to Remember
Katyn." Juneau Empire, 21 April 1988, 5.
Conradi, Peter. "Katyn Forest Was Burial Ground for Russians in 1930s."
Reuter News Agency, 2 August 1989.
Daniszewski, John. "`Katyn' Unspoken by Gorbachev." Juneau Empire, 12
July 1988.
"The Dark Forest of Katyn." [Editorial] New York Times, 16 August
1982, 14.
Darnton, John. "Polish Dissidents Quietly Mourn Wartime Massacre." New
York Times, 4 May 1980, 3.
Echikson, William. "Katyn: The `Blank Space' Soviet Leader Did Not
Fill." Christian Science Monitor, 12 July 1988, 7.
Fein, Esther B. "The Deep Forest of Katyn Keeps Its Bleak Mystery."
New York Times, 7 July 1989, A1.
Gans, Charles J. "Polish Official Raises Issue of WWII Massacre."
Juneau Empire, 11 March 1988.
"General Sikorski with Mr. Churchill." Times (London), 16 April 1943,
3.
"Gorbachev Hands over Katyn Papers." New York Times, 14 April 1990, A5.
Gurnov, Aleksandr. "Brzezinski, Matlock Attend Katyn Memorial Service"
[in Russian]. Moscow Television Service. 30 October 1989, 1800
GMT. FBIS-SOV-89-211.
"Historian: Soviets behind Massacre." Macomb Journal, 22 August 1989,
11.
"In the Soviet Paradise." [Editorial] Washington Post, 25 June 1984,
A10.
"Katyn Forest Murders." [Letter] Wall Street Journal, 23 November
1987.
Kaufman, Michael T. "Poland Erects Ambiguous Memorial to Victims of
Katyn Massacre." New York Times, 10 April 1985, A8.
Kaufman, Michael T. "Poles Uncover a Mass Grave and Open Wartime
Wound." New York Times, 16 July 1987, A14.
Levin, Bernard. "Britain's Complicity in a Chronicle of Shame." Times
(London), 23 April 1990, 12.
Levin, Bernard. "Stalin's Authorised Massacre: History Will Not
Believe That Men of Our Century Could Organise Mass Murder in Cold
Blood as the Russians Did at Katyn." Times (London), 13 April
1993, 14.
McEwen, Andrew. "Katyn Photographs Found in U.S. Archives." Times
(London), 18 July 1989, 10.
MacKenzie, Donald. "The War Today." Macomb Daily Journal, 27 April
1943, 4.
"Moscow Denies Charge." New York Times, 16 April 1943, 4.
"Moscow Paper Blames Soviets in 1940 Deaths." New York Times, 23 March
1990, A9.
"Moscow's Statement on Katyn Massacres." New York Times, 15 October
1992, 6.
"Nazis Accuse Russians." New York Times, 16 April 1943, 4.
"Nixon Sees Khatyn, a Soviet Memorial, Not Katyn Forest." New York
Times, 2 July 1974, 3.
"Pact with Russia Angers Some Poles: Draft Is Silent on Question of
Stalin's Acts During War." New York Times, 22 May 1992, A7.
Pear, Robert. "Book on Massacre of Poles Gets U.S. Funding." New York
Times, 18 September 1988, 4.
Perlez, Jane. "Yeltsin Seems to Accept Polish Bid for Role in NATO."
New York Times, 26 August 1993, 3.
"Poland Charges Soviets with WWII Massacre." Chicago Tribune, 8 March
1989, A1.
"Poles Gather to Pay Homage to the Dead." Anchorage Times, 2 November
1987.
Rosen, James. "Newspaper: Soviets Guilty of Katyn Massacre." United
Press International, 21 March 1990.
"Russia and Poland." [Editorial] Times (London), 28 April 1943, 5.
"Russians Join Walesa to Honor Katyn Dead." New York Times, 24 May
1992, 7.
Schwartz, Stephen. "Intellectuals and Assassins--Annals of Stalin's
Killerati." New York Times Book Review, 24 January 1988, 3, 30-
31.
"Soviet-Polish Historians Address `Blank Spots.'" Pravda, 12 March
1988, 2nd ed., 4.
"Soviets Blamed in '42 Massacre." Chicago Tribune, 17 February 1989, 4.
Stone, Norman. "Katyn: The Heart of Stalin's Darkness." Sunday Times
(London), 15 April 1990.
Tarnowski, Andrew. "Poles Challenge Soviets to Open Files on Katyn
Massacre." Washington Times, 23 March 1988.
"Terrible Mystery of Katyn: Edging Toward the Truth." New York Times,
17 July 1989, A1.
"USSR Requested to Investigate Katyn Murders" [in Polish]. Warsaw
Television Service, 12 October 1989, 1830 GMT. FBIS-EEU-89-197.