Give the names of universities with number of students ranges from 400 to 1000.
number of students ranges from 400 to 1000 refers to num_students BETWEEN 400 AND 1000; name of university refers to university_name
SELECT DISTINCT T2.university_name FROM university_year AS T1 INNER JOIN university AS T2 ON T1.university_id = T2.id WHERE T1.num_students BETWEEN 400 AND 1000