Rolling simplexes and their commensurability. II (a lemma on the directrix and focus)
O. V. Gerasimova

This publication is cited in the following articles:

1. O. V. Gerasimova, Yu. P. Razmyslov, “Frobenius differential-algebraic universums on complex algebraic curves”, Moscow University Mathematics Bulletin, 73:4 (2018), 131–136