Question about building my army.

Ok so whilst tweaking my 600pt list I came upon a question. My panssari company says I can take 2 platoons of jaakari infantry as weapons platoons. Now, in the eastern front book there is no jaakari list, just a recce platoon option. Now, the jaakari have their own list as a PDF and they loose their recce status there but are a little cheaper. Would it be legal for me to use the jaakari platoons from the jaakari briefing?

You either use the book or PDF.

Isn't the PDF sort of an addon for the book? Since it left out the jaakari. But either way I'm building a panssari unit not a jaakari unit. But the only infantry I can field is jaakari but the book only has them as a recce unit. Ive heard of a few other armies that let you bring units from other books or PDFs. So I guess what I'm asking is what determines wether or not you can do that?

In my experience the pdf will let you know if you can use anything with an adjoining book. Not the other way around.

Yea the only time I have seen this allowed is with the IS-85 Heavy Tank company where is says that they can be taken as a heavy tank company in any list that has the option to field KV-85's.

So I would say it must be stated they replace something.

Yep, checked in there and though there are all kinds of references to the Jaakari merging with the panssari to create an armored division nothing says I can use them together