Acknowledgment of sources
Authors should ensure that they have properly acknowledged the work of others, and should also cite publications that have been influential in determining the nature of the reported work. Information obtained privately (from conversation, correspondence or discussion with third parties) must not be used or reported without explicit, written permission from the source. Authors should not use information obtained in the course of providing confidential services, such as refereeing manuscripts or grant applications, unless they have obtained the explicit written permission of the author(s) of the work involved in these services