Resource questions

[starlifter5]

If you use a published resource to help in designing your missions, should you cite that source as a reference?  We used to do this for term papers in college but I'm not sure if this qualifies.  Maybe it's more of an etiquette issue. :-/  While were on the subject, if you use someones scenery, a/c, etc.  What's the process of getting permission?  Sending an email?

[Tango_Romeo]

In the first instance, it's a matter of etiquette. 

And and email contact is appropriate in the latter.  8-)