<h1>Engel, Albert Edward John</h1> <h2>Monograph from <a href="https://authors.library.caltech.edu">CaltechAUTHORS</a></h2> <ul> <li>Engel, A. E. J. (1952) <a href="https://resolver.caltech.edu/CaltechAUTHORS:20230710-967034700.1">Quartz crystal deposits of western Arkansas</a>; <a href="https://doi.org/10.3133/b973e">10.3133/b973e</a></li> </ul>