Free vitamin D is independently associated with systolic blood pressure in diabetic patients with impaired kidney function - Zeng, Shufei; Bachert, Daniela; Pavkovic, Mira; Sandner, Peter; Hocher, Carl-Friedrich; Tsuprykov, Oleg; Morgera, Stanislao; Krämer, Bernhard; Hocher, Berthold; Elitok, Saban (Clinical nephrology, 2022)