Dave Canterbury and the 10 C’s of survivability is a great article on the top ten core items that he feels are necessary when putting together a survival kit. The ten items cover everything from making fire and shelter to having light and being able to repair the few items you have. Dave is very well known and provides survival training at The Pathfinder School school in Ohio. He has many videos on you tube if you are interested.
He is very knowledgeable and you can learn a lot watching his videos. This article has two videos. The first is on the first 5 c’s and the second is a quick run down on the second 5 c’s. He also has many books on bushcraft and survival out , like Advanced Bushcraft: An Expert Field Guide to the Art of Wilderness Survival, that should be in all survival libraries. He has all the experience and it is smart to learn from the best.