Below are a number of suggestions for sourcing books and journal articles.
Many high street booksellers stock a range of educational titles. If the title you require is not in stock, an order can be placed.
Most publishers have websites where you can purchase books directly. Many international booksellers will have UK-based websites for purchasing books and other material. There are also a number of web-based booksellers.
Academic libraries have extensive holdings in specialist areas. They do not generally allow open public access but many facilitate external membership with a range of access arrangements. Check university library information pages for details. Most university libraries now have searchable web-based catalogues in the public domain.
Many journal articles can be purchased online through the publisher’s website. You can subscribe to a whole journal, or you can often buy a single article. Prices vary.
You can search the British Library online for articles published in the last five years, download them, or have them delivered electronically. Non-registered customers can pay by credit card.
http://direct.bl.uk/bld/Home.do
You can also request copies of articles to be delivered by post through Articles Direct.
https://www.bl.uk/services/document/lexformn.html
Many organisations use the inter-library loan service. Check with your organisation's library service.