Lipsiae et Berolini: Typis et in aedibus B.G. Teubneri 1912. XII, 370,  pages. 21.5 x 29 cm. Card covers with printed paper overlay. Spine browned, with some scuffing. Boards slightly bowed. Clean internally. Text in Latin. Very Good. Boards. 
Volume XX in Euler's Opera Omnia, Series One, Opera Mathematica. Part 2 of this title, Volume XXI, was published the following year.
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