From the summary: “We investigate integral polynomials of the form \(f(X) = A^2 X^2 + 2 B X + C\), where \(B^2 - A^2 C = 1\), and provide infinite families wherein the period length of the simple continued fraction expansion of \(\sqrt{f(X)}\) is fixed and independent of \(X\) for given \(A\), \(B\), \(C\). Furthermore, we show that by a judicious choice of \(A\), \(B\), \(C\), we may produce period lengths of \(\sqrt{f(X)}\) that are bigger than any given \(N \in \mathbb{N}\).”
In brief, this is one of the extended series of papers by the first author et al., once again explaining that one may readily construct periodic continued fraction expansions with period consisting of ‘repeating parts’ and detailing various examples.