  In their study entitled "Constructing bibliometric networks: A comparison
between full and fractional counting," Perianes-Rodriguez, Waltman, & van Eck
(2016; henceforth abbreviated as PWvE) provide arguments for the use of
fractional counting at the network level as different from the level of
publications. Whereas fractional counting in the latter case divides the credit
among co-authors (countries, institutions, etc.), fractional counting at the
network level can normalize the relative weights of links and thereby clarify
the structures in the network. PWvE, however, propose a counting scheme for
fractional counting that is one among other possible ones. Alternative schemes
proposed by Batagelj and Cerin\v{s}ek (2013) and Park, Yoon, & Leydesdorff
(2016; henceforth abbreviated as PYL) are discussed in an appendix. However,
our approach is not correctly identified as identical to their Equation A3.
Here below, we distinguish three approaches analytically; routines for applying
these approaches to bibliometric data are also provided.
