“…These recursions involve initial terms and two-electron integrals. For the initial term f (−1, 0, 0, 0, 0, 0) as a function of w 1 , These extended Hylleraas integrals are necessary for the calculation of relativistic effects in lithium and light lithium-like ions [5,6,7,8]. One interesting goal is the high precision calculation of the lithium hyperfine splitting [18], which can serve as a benchmark result for other less accurate methods.…”