Математика. Комплексные числа. Геометрия на плоскости [Электронный ресурс]: учебное пособие / Д.А. Тархов, К.А. Дубаренко, Е.С. Единова, А.М. Никулин, Т.А. Шемякина; Санкт-Петербургский государственный политехнический университет. — Электрон. текстовые дан. (1 файл : 761 Кб). — СПб., 2012. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать). — Текстовый документ. — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2627.pdf>.
| Period | Read | Copy | Open | Total | ||
|---|---|---|---|---|---|---|
| Year 2012 | Quarter 4 | 0 | 0 | 4 | 0 | 4 |
| Year 2013 | Quarter 1 | 4 | 0 | 4 | 0 | 8 |
| Quarter 2 | 21 | 0 | 5 | 0 | 26 | |
| Quarter 3 | 17 | 0 | 10 | 0 | 27 | |
| Quarter 4 | 24 | 0 | 6 | 0 | 30 | |
| Year 2014 | Quarter 1 | 20 | 0 | 5 | 0 | 25 |
| Quarter 2 | 14 | 0 | 4 | 0 | 18 | |
| Quarter 3 | 14 | 0 | 3 | 0 | 17 | |
| Quarter 4 | 14 | 0 | 15 | 0 | 29 | |
| Year 2015 | Quarter 1 | 18 | 0 | 18 | 0 | 36 |
| Quarter 2 | 23 | 0 | 9 | 0 | 32 | |
| Quarter 3 | 11 | 0 | 8 | 0 | 19 | |
| Quarter 4 | 16 | 0 | 7 | 0 | 23 | |
| Year 2016 | Quarter 1 | 28 | 0 | 16 | 0 | 44 |
| Quarter 2 | 11 | 0 | 5 | 0 | 16 | |
| Quarter 3 | 17 | 0 | 4 | 0 | 21 | |
| Quarter 4 | 23 | 0 | 15 | 0 | 38 | |
| Year 2017 | Quarter 1 | 12 | 0 | 4 | 0 | 16 |
| Quarter 2 | 7 | 0 | 8 | 0 | 15 | |
| Quarter 3 | 16 | 0 | 13 | 0 | 29 | |
| Quarter 4 | 8 | 0 | 21 | 0 | 29 | |
| Year 2018 | Quarter 1 | 10 | 0 | 15 | 0 | 25 |
| Quarter 2 | 8 | 0 | 10 | 0 | 18 | |
| Quarter 3 | 17 | 0 | 23 | 0 | 40 | |
| Quarter 4 | 24 | 0 | 22 | 0 | 46 | |
| Year 2019 | Quarter 1 | 16 | 0 | 18 | 0 | 34 |
| Quarter 2 | 8 | 0 | 9 | 0 | 17 | |
| Quarter 3 | 10 | 0 | 10 | 0 | 20 | |
| Quarter 4 | 2 | 0 | 16 | 0 | 18 | |
| Year 2020 | Quarter 1 | 8 | 0 | 16 | 0 | 24 |
| Quarter 2 | 18 | 0 | 4 | 0 | 22 | |
| Quarter 3 | 7 | 0 | 0 | 0 | 7 | |
| Quarter 4 | 11 | 0 | 7 | 0 | 18 | |
| Year 2021 | Quarter 1 | 81 | 0 | 7 | 0 | 88 |
| Quarter 2 | 29 | 0 | 11 | 0 | 40 | |
| Quarter 3 | 16 | 0 | 7 | 0 | 23 | |
| Quarter 4 | 6 | 0 | 9 | 0 | 15 | |
| Year 2022 | Quarter 1 | 26 | 0 | 10 | 0 | 36 |
| Quarter 2 | 8 | 0 | 14 | 0 | 22 | |
| Quarter 3 | 31 | 0 | 6 | 0 | 37 | |
| Quarter 4 | 55 | 0 | 12 | 0 | 67 | |
| Year 2023 | Quarter 1 | 47 | 0 | 17 | 0 | 64 |
| Quarter 2 | 17 | 0 | 11 | 0 | 28 | |
| Quarter 3 | 28 | 0 | 8 | 0 | 36 | |
| Quarter 4 | 10 | 0 | 19 | 0 | 29 | |
| Year 2024 | Quarter 1 | 5 | 0 | 14 | 0 | 19 |
| Quarter 2 | 12 | 0 | 24 | 0 | 36 | |
| Quarter 3 | 28 | 1 | 32 | 0 | 61 | |
| Quarter 4 | 1 | 0 | 7 | 0 | 8 | |
| Total | 857 | 1 | 542 | 0 | 1,400 | |