of (30.2.1) with μ=m and λ=λnm(γ2) are real when z∈(1,∞),
and their principal values (§4.2(i)) are obtained by analytic
continuation to ℂ∖(-∞,1].
with An±m(γ2) as in (30.11.4).
For further properties see Arscott (1964b).
For results for Equation (30.2.1) with complex parameters see
Meixner and Schäfke (1954).