Whenever you find a journal article or book that seems relevant and useful, you can use it as an introduction to other information.
In the library books on one subject are often shelved together. This means that if you find one useful book on the shelves, there will probably be others nearby. For electronic books in the Wageningen UR library, you can use the categories as virtual shelves.
Most academic publications contain reference lists that show where the author obtained the information cited in the publication. You can use these references to find other (older) information.
Some databases (i.e. Web of Science, Scopus, SciFinder on the Web, PsycINFO) store the references in reference lists, and enable you to use them in a search. In these databases you can search forward from an older article or book by an author that you know about, to more recent publications on the same subject which have cited that author. An important work can be recognised by the number of times it has been cited, and is therefore likely to be of particular interest.
Another option that databases might offer is the possibility to search for "Related articles". Related articles are based on number of references that articles have in common (Web of Science, Scopus). Articles which cite the same reference are likely to be about similar areas of research. In PubMed the Related article option is based on the similarity in MeSH terms and words from title and abstract.