Best way to share object instances between modules?

Hi,
I have an application divided into several modules and I need to share
on object that represents my application module between other modules.
I have created a module name "Catalog" which implements all the
features needed by my application, but I need other module to access
one particular instance. How can I share this particular instance? Is
there any suggested way?

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Sem mais e com os melhores cumprimentos,

Sérgio Lopes