Title: Leonida Tonelli
Content:  Leonida Tonelli (19 April 1885 – 12 March 1946) was an Italian mathematician, noted for creating Tonelli's theorem, a variation of Fubini's theorem, and for introducing semicontinuity methods as a common tool for the direct method in the calculus of variations.
Title: Leonida Tonelli
Content:  Tonelli graduated from the University of Bologna in 1907; his Ph.D. thesis was written under the direction of Cesare Arzelà.
Title: Leonida Tonelli
Content:  Leonida Tonelli (held in Rome on May 6–9, 1985). ; . "Leonida Tonelli and the Pisa mathematical school" is a survey of the work of Tonelli in Pisa and his influence on the development of the school, presented at the International congress in occasion of the celebration of the centenary of birth of Mauro Picone and Leonida Tonelli (held in Rome on May 6–9, 1985). The Author was one of his pupils and, after his death, held his chair of mathematical analysis at the University of Pisa, becoming dean of the faculty of sciences and then rector: he exerted a strong positive influence on the development of the university. ; 
Title: Leonida Tonelli
Content: . The "Yearbook" of the renowned Italian scientific institution, including an historical sketch of its history, the list of all past and present members as well as a wealth of information about its academic and scientific activities. ; , available from the Biblioteca Digitale Italiana di Matematica. ; . "The work of Leonida Tonelli and his influence on scientific thinking in this century" (English translation of the title) is an ample commemorative article, reporting recollections of the Author about teachers and colleagues, and a detailed survey of his and theirs scientific work, presented at the International congress in occasion of the celebration of the centenary of birth of Mauro Picone 
Title: Leonida Tonelli
Content:  occasion of the celebration of the centenary of birth of Mauro Picone and Leonida Tonelli (held in Rome on May 6–9, 1985), by Giovanni Battista Rizza on behalf of the University of Parma: the scientific relations between Leonida Tonelli and the Department of Mathematics in Parma are described. ; . The commemoration of Tullio Levi Civita, Guido Fubini, Leonida Tonelli and Michele De Franchis published on the "Annali di Matematica". Note that the paper is not signed: the Author is disclosed by. ; . Some recollections about Mauro Picone and Leonida Tonelli, presented by Ian Sneddon as the "participating address" (Italian translation of the title of the contribution) to 
Title: Maria Valentina Tonelli
Content:  Maria Valentina Tonelli (16 April 1939 – 9 February 2016) was an Italian pharmacist, essayist and editor.
Title: Annalena Tonelli
Content:  Annalena Tonelli (2 April 1943 &ndash; 5 October 2003) was an Italian lawyer and social activist. She worked for 33 years in East Africa, where she focused on tuberculosis and HIV/AIDS prevention and treatment, campaigns for eradication of female genital mutilation, and special schools for hearing-impaired, blind and disabled children. In June 2003, Tonelli was awarded the Nansen Refugee Award, which is given annually by the UNHCR to recognize outstanding service to the cause of refugees. In October 2003, she was killed inside her hospital by two gunmen.
Title: Leonida Tonelli
Content:  International congress on the occasion of the celebration of the centenary of birth of Mauro Picone and Leonida Tonelli (held in Rome on May 6–9, 1985) on behalf of the Royal Society of London and of the Royal Society of Edinburgh. . Some recollections about Mauro Picone and Leonida Tonelli, presented by Ian Sneddon as the "participating address" (Italian translation of the title of the contribution) to the International congress on the occasion of the celebration of the centenary of birth of Mauro Picone and Leonida Tonelli (held in Rome on May 6–9, 1985) on behalf of the Royal Society of London and of the Royal Society of Edinburgh. 
Title: Lamberto Cesari
Content: . "The work of Leonida Tonelli and his influence on scientific thinking in this century" (English translation of the title) is an ample commemorative article, reporting recollections of the Author about teachers and colleagues, and a detailed survey of his and theirs scientific work, presented at the International congress in occasion of the celebration of the centenary of birth of Mauro Picone and Leonida Tonelli (held in Rome on May 6–9, 1985). . "The work of Leonida Tonelli and his influence on scientific thinking in this century" (English translation of the title) is an ample commemorative article, reporting recollections of the Author about teachers and colleagues, and a detailed survey of his and theirs scientific work, presented at the International congress in occasion of the celebration of the centenary of birth of Mauro Picone and Leonida Tonelli (held in Rome on May 6–9, 1985). 
Title: Lamberto Cesari
Content:  "The work of Leonida Tonelli and his influence on scientific thinking in this century" (English translation of the title) is an ample commemorative article, reporting recollections of the Author about teachers and colleagues, and a detailed survey of his and theirs scientific work, presented at the International congress in occasion of the celebration of the centenary of birth of Mauro Picone and Leonida Tonelli (held in Rome on May 6–9, 1985). . "The work of Leonida Tonelli and his influence on scientific thinking in this century" (English translation of the title) is an ample commemorative article, reporting recollections of the Author about teachers and colleagues, and a detailed survey of his and theirs scientific work, presented at the International congress in occasion of the celebration of the centenary of birth of Mauro Picone and Leonida Tonelli (held in Rome on May 6–9, 1985). 

Question: What is Leonida Tonelli's occupation?
Answer: mathematician.