WARSAW, Poland (AP) — Several major Polish media companies are joining forces to put some of their best online content behind a combined paywall — an attempt to maintain revenue as print readership declines.

The initiative, known as Piano, has already been implemented with success in Slovakia and Slovenia, where people pay a small one-time fee for unlimited access to a range of websites. Poland, with 19.5 million Internet users in a nation of 38 million, represents the first large market to try this pay model, and how it fares could determine whether it takes hold in other countries.