Dear Murad,

please have a look at this URL address:

https://www.ohio.edu/mechanical/stirling/

and at the book attached...

Respectfully yours,

Evgeni

Dear Evgeni,

Thank you very much for your help,

I also wish to have an idea on other free energy engines. 

Dear Mourad,

I could give you the following literature recommendations (cf. the attachement)...

Every success!

Respectfully yours,

Evgeni

Thank you Mr. Evgeni for these valuable documents.

Mourad