Mammillaria beneckei

Hi, I am from Belgium.
Since a couple of months I am searching for a Mammillaria beneckei. But no luch until now!
Is there somebody who can tell me where to find one?
Best regards,
Martine

I am answering from Sombrerete, Zacatecas, Mexico, where I am at this moment of my Mexico trip. The DeHerdt nursery used to sell M. beneckei, but perhaps they don't anymore.
I do have a few M. beneckei, among them a few seedlings, which hopefully are still alive when I return to The  Netherlands in a couple of days.
M. beneckei is quite sensitive to cold. I used to have some nice seed-grown plants, but then, one winter I was too late bringing them into my house and they all died. Minimum temperature at least 5 deg C, but preferably higher.

Wolter ten Hoeve.