Hazel (Sellwood) Christensen, 90, of 212 Hamilton St., Hartford, widow of Rosmer Bruce Christensen, died Monday (May 17) at Mount Sinai Hospital. Born in Quebec, Canada, she lived in Hartford for most of her life. She was employed by First National Stores, Wethersfield, for many years before retiring. She leaves a daughter, Patricia Givens of Hartford; four sons, Robert B. Christensen of Windsor, John L. Christensen of Shelbyville, Tenn., Richard C. Christensen of Philadelphia, Pa., and Rosmer J