Boris Z. Shapiro, Alek Vainshtein. On the number of connected components in the space of M-polynomials in hyperbolic functions. Adv. Appl. Math., 30(1-2):273-282, 2003. [doi]
@article{ShapiroV03,
title = {On the number of connected components in the space of M-polynomials in hyperbolic functions},
author = {Boris Z. Shapiro and Alek Vainshtein},
year = {2003},
doi = {10.1016/S0196-8858(02)00536-5},
url = {https://doi.org/10.1016/S0196-8858(02)00536-5},
researchr = {https://researchr.org/publication/ShapiroV03},
cites = {0},
citedby = {0},
journal = {Adv. Appl. Math.},
volume = {30},
number = {1-2},
pages = {273-282},
}