On the rotational motion of solid bodies around a variable axis
Euler shows that every body has at least one set of three orthogonal principal axes. This paper gives rise to a branch of algebra. (Based on Clifford Truesdell's An idiot's fugitive essays on science: methods, criticisms, training, circumstances.)
Original Source Citation
Mémoires de l'académie des sciences de Berlin, Volume 14, pp. 154-193.
Opera Omnia Citation
Series 2, Volume 8, pp.200-235.