Gillieson, D., Gunn, J.,  Auler, A. & Bolger, T. (Eds.) (2022) Auler A., Bolger T. Didonna F., Eberhard R., Eberhard S., Gestner H., Gillieson D., Gunn J. Komericki A., Matias D. Moreira M., Reboleira A.S.P.S., Schindel G., Tirla M.L., Vogel B. Wuest B. (Contributors) Guidelines for Cave and Karst Protection. Second Edition. Published by the International Union of Speleology and the International Union for Conservation of Nature. 112 pp. ISBN:978-0-646-84911-9.