2 citations to https://www.mathnet.ru/rus/tvp1644

1. A Samoletov, B Vasiev, “Advanced selection of ensemble control tools”, J. Phys.: Conf. Ser., 2090:1 (2021), 012059  
2. Paul B Slater, “Essentially all Gaussian two-party quantum states area priorinonclassical but classically correlated”, J. Opt. B: Quantum Semiclass. Opt., 2:4 (2000), L19