Like others said , you can't. Quite often when I print from a browser, I "print-to-file" and can make as many copies as I want. The best solution, although not the only one, is to print a unique identifier , like a barcode, on each document, and store them in a database. You can then get "very creative" on how to use your database to check veracity of the documents.

For instance with "entrance passes", you could have the purchaser upload a photo of who will be using the pass, then when the passes are barcode-scanned, the photo associated with that barcode must look like the person using the pass.

You don't say how your "series numbers" are being used, but you could probably work out some scheme, even charge clients extra if their vochers are used more than once. Barcodes make this easy.