While "free download" sites often carry copyright risks or malware, you can access the material through the following legitimate channels:
Many educational communities on VK (like "Biology Books") share PDF versions of older editions for preview purposes. For instance, a 2016 version involving Sumatokhin has been shared in community groups . While "free download" sites often carry copyright risks
You can find electronic versions and teaching aids on the official Prosveshcheniye Media Library , which often provides digital access to textbooks and workbooks. While "free download" sites often carry copyright risks