Chau, D.
(2002).
 On the asymptotic equivalence of linear differential equation in hilbert spaces.
<em>VNU Journal Of Science: Mathematics - Physics, 18</em>(2).
Retrieved from <a href="https://js.vnu.edu.vn/MaP/article/view/3310" target="_new">https://js.vnu.edu.vn/MaP/article/view/3310</a>