Functional Observers for Dynamical Systems

The individual or group credited with creating the content of a product, such as an author for books, a director for films, or a designer for apparel. It represents the creative contributor responsible for the primary intellectual property.

The physical or digital form of a book, such as paperback, hardcover, audio CD, or board book. It indicates how the content is packaged and presented to readers.

The calendar year in which the product was first made available to the public or released for sale. It is expressed as a four‑digit number (e.g., 2015) and can be used to filter, sort, or compare products by their release period.

The name of the entity that publishes or distributes the product, such as a book, magazine, or other media item.