Plique-a-jour enamelling

Hi, I’ve done quite a bit of research into plique-a-jour
enamelling, and invented a couple of tricks of my own. However,
this is such an amazingly intricate and complex technique that I
would love to know more. Please, if anyone is truly experienced
with this, I would love to hear from you. If anyone is aware of
any awesome books on the subject, could you please tell me what
they are? And, finally, if anyone is aware of any classes or
anyone who is willing to teach this subject, please tell me.

Thanks tonnes and tonnes!