HUN-REN Research Centre for Astronomy and Earth Sciences
Konkoly Thege Miklós Astronomical Institute

Binary stars among Galactic classical Cepheids (László Szabados):

https://cep.konkoly.hu//intro.html

Extragalactic Cepheid Data Base (Dóra Tarczay-Nehéz, László Szabados):

https://cepheids.konkoly.hu/