Linear Systems Theory

EXPECTED DELIVERY DATE

The Estimated Delivery Date is a non-binding forecast that analyzes several factors, such as: the availability of stock of the item, the transit time to the destination address, the processing time, among others. The expected delivery date may be subject to changes and recalculations, in the following non-exclusive scenarios: if payment is not made immediately; the customer changes his order; there is a difference in the availability of an item; need for an additional payment; among others. You can check the expected delivery date of your order in the last step of checkout and confirm it in the order details from the customer area.

IN STOCK

At least one unit of this item is available in our warehouse. Subject to confirmation after payment.

PRERELEASE

The date shown corresponds to the date of the release of the item on the market. Orders will be delivered on the release date if registered and paid for up to 48 working hours before that date and to addresses in mainland Portugal. For orders registered after this deadline or to other destinations, an estimated delivery date will be indicated.

AVAILABLE

Items that are available from suppliers and will be shipped after receiving the item in our warehouse.

Shipping offer: valid for Standard deliveries and at Collection Points, in mainland Portugal, on orders with a value equal to or greater than €16. For orders under €16, the shipping costs are refunded on a Wookmais card. Extra services such as Saturday delivery and Time Window have an additional cost, not free.

Shipping offer valid only for books and for deliveries in the Azores and Madeira, on all orders sent by Standard Delivery, except books sold on marketplace. Shipping offers valid for orders up to 10 kg.

Promotion valid for orders of non-school books registered until 31/12/2026. Discounts or advantages that cannot be combined with other promotions.