Question: In what year was the economist under whom Hans F. Sennholz studied born?

Context paragraphs:
Hans F. Bauer: Hans F. Bauer (1932 in Hollywood, California – 6 February 2009 in Costa Mesa, California) was an American research chemist.  He was married and had 4 children.

Hans Fróði Hansen: Hans Fróði Hansen (born 24 August 1975 in Leirvík, Faroe Islands) is a retired football player and now manager from the Faroe Islands, who had started a second career as fashion and beauty advisor under the name Hans F. Hansen of Scandinavia.  His main product line was called Below Your Belt and was a series of product intended for pubic hair removal.

Hans Sennholz: Hans F. Sennholz ( ; ] ; 3 February 1922 – 23 June 2007) was a German-born American Austrian School economist and prolific author who studied under Ludwig von Mises.  A Luftwaffe pilot during World War II, he was shot down over North Africa on 31 August 1942, and spent the remainder of the war in a POW camp in the United States.

Hans F. Loeser: Hans F. Loeser (September 28, 1920 – May 15, 2010) was an American lawyer whose activism during the Vietnam War earned him the enmity of Richard Nixon.

Ludwig von Mises: Ludwig Heinrich Edler von Mises ( ; ] ; 29 September 1881 – 10 October 1973) was an Austrian-American theoretical Austrian School economist.  Mises wrote and lectured extensively on behalf of classical liberalism.  He is best known for his work on praxeology, a study of human choice and action.

Hans Dersch: Hans F. Dersch (born December 25, 1967) is an American former competition swimmer and breaststroke specialist who represented the United States at the 1992 Summer Olympics in Barcelona, Spain.  There he won the gold medal in the men's 4×100-meter medley relay, after having swum in the preliminary heats for the winning U.S. team.  Dersch was a two-time gold medalist at the 1991 Pan American Games.

Hans Weinberger: Hans F. Weinberger (September 27, 1928 in Vienna - September 15, 2017 in Durham, North Carolina) is an Austrian-American mathematician, known for his contributions

Fred J. Koenekamp: Frederick James Koenekamp, A.S.C. (November 11, 1922 – May 31, 2017) was an American cinematographer.  He was the son of cinematographer Hans F. Koenekamp.

K. N. Raj: Kakkadan Nandanath Raj (13 May 1924 – 10 February 2010) was a veteran Indian economist.  He is popularly known as K. N. Raj.  He played an important role in India's planned development, drafting sections of India's first Five Year Plan, specifically the introductory chapter when he was only 26 years old.  He was a veteran economist in the Planning Commission.  He worked out a plan to raise India's rate of savings in the post-Second World War period when the country was in need of foreign aid.  He computed India's Balance of Payments for the first time for the Reserve Bank of India.  Raj was an advisor to several prime ministers from Jawaharlal Nehru to P.V. Narasimha Rao.  Dr. Raj was a Keynesian economist.  He studied the application of Keynesian monetary theory in Indian context.

Hans Raffert: Hans F. Raffert (March 11, 1927 – March 3, 2005) was a German American chef who was White House Executive Chef from 1988 to 1992.  He was the first White House chef to annually build a gingerbread house for the Executive Residence's Christmas holiday decorations.

Supporting paragraphs: Hans Sennholz Ludwig von Mises
Answer: 1881