Calendar operator practices — Guidelines to protect against calendar abuse 333:20183332018-10-31T00:00:00Z Messaging Malware and Mobile Anti-Abuse Working Group M3AAWG Thomas Schäfer, 1&1 Mail&Media Development and Technology GmbH Jesse Thompson, University of Wisconsin-Madison Messaging Malware and Mobile Anti-Abuse Working Group M3AAWG12018-10-31T00:00:00Zendraft2018 Messaging Malware and Mobile Anti-Abuse Working Group M3AAWGreportCalConnect TC CALSPAM