Below is one of the rare works authored by Obama from his Columbia days:
Breaking the War Mentality, Columbia U. Sundial 1983
Since Obama is acting as an advocate for the groups mentioned in the article, it is safe to assume that he was fairly familiar with the people mentioned in it. Below is more background on these individuals:
Paul Martin - Director of Earl Hall (Earl Hall is Columbia's religious and community service HQ) at Columbia University in 1983
J. Paul Martin is professor and director of human rights studies at Barnard College. He teaches such courses as "Human Rights and Social Change in Sub-Saharan Africa," and is affiliated with the Africana studies program.
Mark Bigelow - Union Theological Seminary Student in 1983 and Intern for ARM (Arms Race Alternatives)
He is currently pastor of the United Church of Christ in Huntington, NY. It was founded in 1955 by a group of Congregationalists who saw a need for a progressive Protestant Church in the township of Huntington.
His two primary areas of interest are interfaith dialogue and religion and sexuality. He is on the Board of Directors for the Planned Parenthood Federation of American where he has chaired their long-range planning committee.
Curiously, Mark Bigelow does not remember either the article or being interviewed by Obama:
“In March 1983 an article appeared in the Columbia Sundial, a monthly student newsmagazine, written by a young undergraduate named Barack Obama. In it he quotes me, several times, about the work of ARA and the need for nuclear disarmament. (You can view the article at http://www.scribd.com/doc/10499043/Barack-Obama-Breaking-the-War-Mentality-March-10-1983-Sundial.)
"The personally sad part of the story is that I cannot remember any of this. I don’t remember being interviewed and I didn’t even know of the existence of the article until this week. It is wild to think that Obama and I crossed paths and that he quoted me in this article. It is fun to think of the connection and tell the story.” -Mark Bigelow on his recollections of Obama
For more on Mark's recollections, please look up the article using the search feature (search Obama) of the blog. It is entitled “If only I could remember” on May 20th 2009.
Mark Bigelow - Pastor Blog
Even though it is a common name, this Resume places R. Kahn at Columbia during 1983:
(While you are reading this, contrast Khan's publications with those attributed to Obama.)
R. Kahn CV with Dates
Robert Kahn - Junior at Columbia and member of SAM (Students Against Militarism) in 1983
Robert Kahn was born in Brookline, Massachusetts. After graduating from Columbia University with a B.A in history, he went to N.Y.U. Law School where he was a Notes and Comment Editor for the Review of Law and Social Change and a member of the Order of the Coif. He clerked for Magistrate-Judge Leonard Bernikow of the Southern District of New York and worked as a staff attorney at Harlem Legal Services. Prior to coming to the School of Law, Kahn taught legal writing for six years at Brooklyn Law School.
Kahn also holds a Ph.D. political science from Johns Hopkins University. His scholarship has focused on the use of legal sanctions against Holocaust deniers in Western Europe and North America. His book, Holocaust Denial and the Law: A Comparative Study, was published in 2004 by Palgrave-MacMillan. Kahn has also published articles on the cross-burning cases (RAV v. St. Paul and Virginia v. Black), and the constitutionality of restrictions on the Muslim headscarf in the United States and Germany. More recently, Kahn has turned his attention to the Danish Cartoon controversy and how it has triggered a new European debate over the boundary between freedom of speech and hate speech
Committee in Solidarity with the People of El Salvador
The Committee in Solidarity with the People of El Salvador, based in Washington, D.C., is a national activist organization with chapters in various cities in the United States. CISPES supports the Farabundo Martí National Liberation Front and the progressive social movement in El Salvador.
CISPES was founded in 1980 in opposition to the U.S. aid (funding and political support) to the Salvadoran military and government during the Salvadoran civil war. CISPES opposed the politics and the actions of the right-wing Nationalist Republican Alliance (ARENA) and its leader Roberto D'Aubuisson during the Salvadoran Civil War, and continues to oppose the policies that ARENA implements.
More background on Obama's Columbia University Years from Zombie Times