Harold M. Konstantelos Books

Three Wise Cats: A Christmas Story

By Terri Jenkins-Brady, Harold M. Konstantelos, Harold Konstantelos

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An inspiration tale about three cats and their journey to witness the first Christmas.The old Siamese Ptolemy was alongside his master when a star of unusual brightness was seen in the heavens, in...

Three Wise Cats: A Christmas Story

By Terri Jenkins-Brady, Harold M. Konstantelos, Harold Konstantelos

Average: 0.00, 0 Ratings

The old Siamese Ptolemy was alongside his master when a star of unusual brightness was seen in the heavens, indicating an event of momentous significance, and leading to a great quest. Ptolemy must...

Oh Pegasus

By Harold Konstantelos

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Three Wise Cats

By Lyssa Browne, Harold Konstantelos, Terri Jenkins Brady

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Three Wise Cats

By Harold M. Konstantelos, Terri Jenkins Brady

Average: 0.00, 0 Ratings

Three Wise Cats

By Harold M. Konstantelos

Average: 0.00, 0 Ratings

Three Wise Cats

By Harold Konstantelos, Terri Jenkins Brady

Average: 0.00, 0 Ratings

How to Convert ISBN-10 to ISBN-13 (and Vice Versa): A Complete Guide

If you’re in the world of books—whether as a publisher, librarian, bookseller, or avid collector—you’ve likely come across the terms ISBN-10 and ISBN-13. Understanding these formats and knowing how to convert between them is essential for maintaining consistency and compatibility in book records. In this post, we’ll cover everything you need to know about ISBN conversions, step by step.

What is an EAN and How Does it Relate to an ISBN?

If you’ve ever purchased a product online or in a store, you’ve likely come across a barcode. Behind these barcodes lies a standardized system that makes modern commerce possible. Two key codes often encountered are the EAN (European Article Number) and ISBN (International Standard Book Number). But what are they, how are they connected, and why are they so crucial? Let’s explore.