Ефремова, Светлана Сергеевна. Приведение кривых 2-го порядка к каноническому виду поворотом осей координат [Электронный ресурс]: учебное пособие / С. С. Ефремова, Л. А. Иванова; Санкт-Петербургский политехнический университет Петра Великого. — Электрон. текстовые дан. (1 файл : 1,36 Мб). — Санкт-Петербург, 2018. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/s18-45.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/s18-45>.
| Period | Read | Copy | Open | Total | ||
|---|---|---|---|---|---|---|
| Year 2018 | Quarter 1 | 16 | 0 | 0 | 0 | 16 |
| Quarter 2 | 33 | 0 | 0 | 0 | 33 | |
| Quarter 3 | 15 | 0 | 0 | 0 | 15 | |
| Quarter 4 | 599 | 16 | 0 | 0 | 615 | |
| Year 2019 | Quarter 1 | 101 | 0 | 0 | 0 | 101 |
| Quarter 2 | 50 | 0 | 0 | 0 | 50 | |
| Quarter 3 | 17 | 0 | 0 | 0 | 17 | |
| Quarter 4 | 26 | 0 | 0 | 0 | 26 | |
| Year 2020 | Quarter 1 | 30 | 0 | 0 | 0 | 30 |
| Quarter 2 | 19 | 0 | 0 | 0 | 19 | |
| Quarter 3 | 11 | 0 | 0 | 0 | 11 | |
| Quarter 4 | 21 | 0 | 0 | 0 | 21 | |
| Year 2021 | Quarter 1 | 19 | 0 | 0 | 0 | 19 |
| Quarter 2 | 21 | 0 | 0 | 0 | 21 | |
| Quarter 3 | 12 | 0 | 0 | 0 | 12 | |
| Quarter 4 | 10 | 1 | 0 | 0 | 11 | |
| Year 2022 | Quarter 1 | 3 | 0 | 0 | 0 | 3 |
| Quarter 2 | 8 | 0 | 0 | 0 | 8 | |
| Quarter 3 | 13 | 1 | 0 | 0 | 14 | |
| Quarter 4 | 9 | 0 | 0 | 0 | 9 | |
| Year 2023 | Quarter 1 | 12 | 0 | 0 | 0 | 12 |
| Quarter 2 | 14 | 0 | 0 | 0 | 14 | |
| Quarter 3 | 10 | 0 | 0 | 0 | 10 | |
| Quarter 4 | 16 | 1 | 0 | 0 | 17 | |
| Year 2024 | Quarter 1 | 7 | 0 | 0 | 0 | 7 |
| Quarter 2 | 13 | 0 | 0 | 0 | 13 | |
| Quarter 3 | 6 | 0 | 0 | 0 | 6 | |
| Quarter 4 | 25 | 0 | 0 | 0 | 25 | |
| Year 2025 | Quarter 1 | 16 | 0 | 0 | 0 | 16 |
| Quarter 2 | 16 | 0 | 0 | 0 | 16 | |
| Quarter 3 | 0 | 0 | 0 | 0 | 0 | |
| Total | 1,168 | 19 | 0 | 0 | 1,187 | |