So far i have found that the skin doesn't affect the magnetic strength of the case, I also have a charcoal fabric case which I really like despite some flaws. (blog.the-ebook-reader.com)
The apparent strength of the case, however, is weak. (slaw.ca)
A key strength of the case study method involves using multiple sources and techniques in the data gathering process, which strengthens the study by providing opportunities for triangulation. (citejournal.org)