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2. On computing best 𝐿₁ approximations;Barrodale, I.,1970
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4. H. L. Loeb, On Rational Fraction Approximations at Discrete Points, Convair Astronautics, Math. Preprint #9, 1957.
5. J. C. Mason, Some New Approximations for the Solution of Differential Equations, Doctoral Thesis, Oxford, 1965.