Perturbations Observed in The Orbital Elements of the Spectroscopic Binary 57 Cygni.Published in:Journal of the Iowa Academy of Science, 2018, v. 125, n. 1-4, p. 1, doi. 10.17833/0896-8381-125.1.1By:MCLAUGHLIN, KENNETH W.;PANTHI, JANAKPublication type:Article