He has also written a number of popular scientific articles.

He is the author of more than 130 scientific articles.

He was the author of more than 100 scientific articles and reports.

He has written over 150 scientific articles and three books.

He is an author of more than 90 scientific articles.

He is the author of 6 books and 30 scientific articles.

The author of 32 books and more than 600 scientific articles.

He is the author of many books and scientific articles.

He was the author of more than 70 scientific articles.

Author until 2008 of 40 books and 100 scientific articles.