References:

  1. https://www.baeldung.com/cs/b-tree-data-structure
  2. http://www.btechsmartclass.com/data_structures/b-trees.html
  3. https://people.ksp.sk/~kuko/gnarley-trees/Btree.html
  4. https://www.cs.usfca.edu/~galles/visualization/BTree.html