For those interested in exploring SLA research methods in more depth, the following resources are recommended:
By understanding the research methods and designs discussed in Seliger's work, researchers and educators can contribute to the ongoing development of SLA research, ultimately informing language teaching practices and promoting more effective language learning outcomes. Second Language Research Methods Herbert W Seliger.pdf
Once you have a legitimate copy, do not simply read it. Use it as a workbook: For those interested in exploring SLA research methods