Find $A^2$ , where $A$ is the sum of the absolute values of all roots of the following equation:
$x = \sqrt{19} + \frac{91}{{\sqrt{19}+\frac{91}{{\sqrt{19}+\frac{91}{{\sqrt{19}+\frac{91}{{\sqrt{19}+\frac{91}{x}}}}}}}}}$

Let's think step by step and output the final answer within \boxed{}.
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