# class number of quadratic fields

#### Chems

Hello,
Let $d$ be a positive square free integer
for which $d$ we have $h(\mathbb{Q}(\sqrt{-2d})=8$?

In particular,

if $p\equiv 1 \mod 8$ is a prime, when do we have $h(\mathbb{Q}(\sqrt{-2p})=8$?

is there any references to sugggest for me?

Thank you