Calcium hydroxyapatite, Ca10(PO4)6(OH)2 ceramics prepared by aqueous sol-gel processingBogdanoviciene, Irma; Beganskiene, Aldona; Tõnsuaadu, Kaia; Glaser, Jochen; Meyer, H.-Jürgen; Kareiva, AivarasMaterials research bulletin2006 / p. 1754-1762 https://www.sciencedirect.com/science/article/pii/S0025540806000778