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                                <h1 id="license">License</h1>
<ul>
<li>The contents of this book can be used for free and without charge for individual and non-commercial purposes.</li>
<li>It is allowed to create pdf and epub formats for non-commercial and personal use purposes and copy them to personal devices such as PCs, tablets, and e-book readers. If the reader cannot create the format *self, it is also allowed to ask a friend to create a file.