Formaldehyde observations of Planck cold cores. - Imanaly, Ernar; Esimbek, Jarken; Baan, Willem; Wu, Gang; Berdikhan, Dilda; Li, Dalei; Zhou, Jianjun; Tang, Xindi; He, Yuxin; Komesh, Toktarkhan (Monthly Notices of the Royal Astronomical Society, 2026)