It will be difficult to tell without some experience. The absence of these features does not mean that a book is not reliable, just proceed with caution and check other sources to confirm the information. Primary sources form the backbone of advanced SCA research. Primary sources give a first-hand account of life in the Middle Ages and Renaissance. You will often find primary sources listed in the bibliographies found in secondary sources.
Bibliographies are one of the best places to find more sources.
Not every book you may be interested in will be in your local library's collection. Finding sources through bibliographies will give you the information necessary to request it through inter-library loan from another library. ILL is a cooperative lending service that most libraries participate in. Books are not all you will find in a bibliography. Journal and magazine articles can also be listed.