Mapping cell-to-tissue graphs across human placenta histology whole slide images using deep learning with HAPPY by Vanea, C, Džigurski, J, Rukins, V, Dodi, O, Siigur, S, Salumäe, L, Meir, K, Parks, WT, Hochner-Celnikier, D, Fraser, A, Hochner, H, Laisk, T, Ernst, LM, Lindgren, CM, Nellåker, C