hi cos-top For those who haven't heard the news yet, Helio Fagundes passed away on 30 July. For those not fully familiar with his pioneering work in pushing for cosmic topology as an observational field within cosmology/extragalactic astronomy, here is the ADS list of his work: https://ui.adsabs.harvard.edu/search/q=%20author%3A%22fagundes%2C%20h%22&sor... His first paper with a closed hyperbolic spatial section and an urge to make observational tests with quasars seems to be his 1982 paper: https://ui.adsabs.harvard.edu/abs/1982LMaPh...6..417F Boud