Tipo
Electronic books
122
Libros electrónicos
86
Computer network resources
60
Internet resources
13
Libros electronicos
8
Outlines, syllabi, etc
8
Handbooks, manuals, etc
6
Case studies
3
Examinations
3
Study guides
3
Bibliography
2
Congresses
2
Problems, exercises, etc
2
Amateurs' manuals
1
Certification
1
Directories
1
Formulae
1
Libros de texto
1
Textbooks
1