Seth Lynch 
La compra de Luisiana (The Louisiana Purchase) [PDF ebook] 

When the Louisiana Territory was added to the United States in 1803, it about doubled the size of the young nation. It took years to clarify its boundaries and explore every square mile. How this momentous purchase came to be and its implications on the future of the United States are explained in detail in this book. Uncomplicated maps and simple language help developing readers and those in need of review to understand the many changes in this land that started with its purchase in 1803.