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http://www.kuttaka.org/~JHL/L1758c.pdf
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3. L. Euler, Deformulis exponentialibus replicatis. Reprinted in Leonhard Euleri Opera Omnia, Ser. Prima, Opera Mathematica 15, 268–297 (1927) (original publication year: 1777)
4. L. Euler, De serie Lambertina plurimisque eius insignibus proprietatibus. Acta Academiae Scientarum Imperialis Petropolitinae 2, 29-51 (1783) (original publication year: 1773)
5. reprinted in L. Euler, Opera Omnia, Series Prima, in Commentationes Algebraicae (Teubner, Leipzig, Germany, 1921), 6, 350-369 (1921). http://math.dartmouth.edu/~euler.docs/originals/E532.pdf