except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use of the publication of trade names, trademarks, service marks, or similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. This paper discusses efficient and original computations of the special cases of the generalized Bessel function distributions of the second kind. The journal paper is a masterpiece in the field of numerical methods, numerical linear algebra, and computational mathematics. The entire work in this journal paper is original and never presented before in the literature. The main focus of this journal paper is to fill in the gap or to deal with the special cases that were not covered in the two premier publications of Progri 2016 and 2018. In this journal paper the closed form expression and the efficient computation of the probability density function (pdf) and the cumulative distribution function (cdf) for five special cases is provided. For each generalized Bessel distribution model the closed form expression of the cdfs is given by means of Legendre continued fraction or Taylor series expansion of the modified Bessel functions of the second kind, for both integer and real values of a parameter, which leads to incomplete gamma functions, hypergeometric series, the Kampé de Fériet functions (or double hypergeometric series), and in two special cases of the Srivastava's triple hypergeometric series. Efficient computations of the algorithms (which are implemented in MATLAB functions) are also presented in the paper. Numerical results are derived for each case to validate the theoretical models presented in the paper.