Special Paper Needed For Greeting Cards?

I've just got started with paper crafts. I've made a few little projects from tutorials from YouTube and it's been a blast! No one ever told me how addicting it is to sit down and craft. Sad that I've found out so late.


My current project is building this Crayon Popup Card with a template. I'm not the best at drawing or coming up with something creative. A lifetime in accounting will do that to you.


They never stated what kind of paper I should use? I'm sure I can use regular old printing paper but I'm worried that it'll be all flimsy and easily damaged before I give it to my grandchild.


What do you guys think they used?

I didn't find the right solution from the internet.
References:

http://www.craftforum.com/f2/special-paper-needed-greeting-cards-11025/

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