Can anyone please tell me in what order should I read doukyuusei

1. Doukyuusei (Classmates)
2. Sotsugyousei (Graduate)
3. Sora to Hara. (Spin-off of Doukyuusei & Sotsugyousei. The professor's story, I hate him lol)
4. Occupation to Beloved (O.B.) (Side story of Sora To Hara / Sequel to Sotsugyousei)
• Graduation Certificate - Epilogue, artbook, sequel to O.B.
5. Dousoukai
6. Doukyuusei: Gold Ring & Silver Ring.
7. Blanc.
8. Futari Gurashi (Living Together)
9. Sajou Rihito no Chichi to Sono Buka.