Robert Estalella Books

Discusses the characteristics of the nine planets of the solar system, describing surface features, lengths of days, and natural satellites. Includes suggestions for making a model of the solar sys...

Our star--the sun

By Robert Estalella

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Examines the structure and characteristics of the sun and describes such solar phenomena as sun spots, solar winds, eclipses, and the sun's influence on Earth. Includes an activity on the colors of...

Our satellite--the moon

By Robert Estalella

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Discusses the evolution of the moon, its characteristics, influence on the earth, and appearance during eclipses.

Our planet--Earth

By Robert Estalella

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Describes the earth's formation and its physical characteristics as well as its relation to other bodies in the universe. Includes directions for making a sundial.

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.