. . . . "1240Z"^^ . . . . . "Fibonacci;Pisano, Leonardo; Bonacci, Leonardo; Fibonacci, Leonardo"@en . . "1250Z"^^ . "1170Z"^^ . . . "Italian mathematician and writer" . . . "Leonardo Bonacci (c. 1170 \u2013 c. 1250)\u2014known as Fibonacci (Italian: [fibo\u02C8natt\u0283i]), and also Leonardo of Pisa, Leonardo Pisano Bigollo, Leonardo Fibonacci\u2014was an Italian mathematician, considered to be \"the most talented Western mathematician of the Middle Ages\".Fibonacci popularized the Hindu\u2013Arabic numeral system to the Western World primarily through his composition in 1202 of Liber Abaci (Book of Calculation)."@en . "Leonardo of Pisa"@en .