Desperately looking for E. coli with lambda cI857 Sam7

[Bjorn]

Hi all,
I am looking for an E. coli strain with a lysogenic lambda phage that is practical to induce and purify, such as one with cI857 Sam7.

If you have one, I would be most grateful if you could send it to me.
Alternatively, point me to a resource that is free or not too expensive where I could buy one.

I would like to use it to produce DNA for my own molecular weight markers.
I have found it much harder to find this than I would have thought.

Thanks,

Björn Johansson
Departament of Biology
University of Minho
Campus de Gualtar
4710-057 Braga
PORTUGAL