diff --git a/02.Preparation.pdf b/02.Preparation.pdf
index 8446fae..bae7b5e 100644
Binary files a/02.Preparation.pdf and b/02.Preparation.pdf differ
diff --git a/03.Basic_Concepts_I.pdf b/03.Basic_Concepts_I.pdf
index 4085877..94d6896 100644
Binary files a/03.Basic_Concepts_I.pdf and b/03.Basic_Concepts_I.pdf differ
diff --git a/06.Basic_Concepts_IV.pdf b/06.Basic_Concepts_IV.pdf
index 061ddf9..bcc7bf6 100644
Binary files a/06.Basic_Concepts_IV.pdf and b/06.Basic_Concepts_IV.pdf differ
diff --git a/21.Advanced_Topics_I.pdf b/21.Advanced_Topics_I.pdf
index 7f68b0d..a1524e0 100644
Binary files a/21.Advanced_Topics_I.pdf and b/21.Advanced_Topics_I.pdf differ