These books discuss assessment in education as a topic.
Use these databases to obtain a comprehensive description/review of a test/measurement (i.e. reliability, validity, etc.), publisher information, administration, procedures, cost, audience, etc.
Finding an actual instrument can be difficult due to licensing or author restrictions. However, sometimes the instrument is included, and if not, article results may still reveal relevant content about the test and how it was used in the study. If available, the instrument will usually be located in the appendices. The list of references can also be checked for a possible instrument source location.