An explicit formula for the linearization coefficients of Bessel polynomials II

In this paper, a single sum formula for the linearization coefficients of the Bessel polynomials is given. In three special cases this formula reduces indeed to either Atia and Zeng's formula (Ramanujan Journal, Doi 10.1007/s11139-011-9348-4) or Berg and Vignat's formulas in their proof of the positivity results about these coefficients (Constructive Approximation, {\bf 27} (2008), 15-32). As a bonus, a formula reducing a sum of hypergeometric functions $_3F_2$ to $_2F_1$ is obtained.