Print or Electronic.
Books can be edited compilations are works by a single or group of authors. High School students should look for books by scholarly presses.
Try to find a variety of sources that answer your question. For secondary sources, always use vetted, scholarly sources and try not to rely exclusively on one source. Remember you are using sources to build your own argument and add your own analysis.
Primary sources enable a researcher to analyze evidence created during the time period without relying on the viewpoints of scholars. When searching for primary sources, seek different viewpoints about your topic. The better your sources, the better your research paper will be!
Images from "Thinking Critically about Information: “Good” and “Bad” Source Types" PowerPoint created by Kevin Klipfel, Information Literacy Coordinator, California State University, Chico. Contact: kklipfel@csuchico.edu.