diff --git a/Weeks/Week3.md b/Weeks/Week3.md
index d50e980..3438959 100644
--- a/Weeks/Week3.md
+++ b/Weeks/Week3.md
@@ -22,7 +22,7 @@ Week 3. Computational methods for time-dependent Partial Differential Equations
 <i>4. Theory: Space frames [4.3](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/space_frame.html)</i> <br>
 {: .content }
 
-[Workshop 6](https://teachbooks.tudelft.nl/computational-modelling/dynamics/Exercises/Workshop_FEM_dyn_rod.html)<br>
-[Workshop 7](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/Exercises/Workshop_FEM_dyn_beam.html)<br>
-[Workshop 8](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/Exercises/Workshop_FEM_dyn_space_frames.html)<br>
-{: .exercises }
\ No newline at end of file
+[Workshop 1](https://teachbooks.tudelft.nl/computational-modelling/dynamics/Exercises/Workshop_FEM_dyn_rod.html)<br>
+[Workshop 2](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/Exercises/Workshop_FEM_dyn_beam.html)<br>
+[Workshop 3](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/Exercises/Workshop_FEM_dyn_space_frames.html)<br>
+{: .exercises }
diff --git a/Weeks/Week4.md b/Weeks/Week4.md
index ea252c8..eb3b6c1 100644
--- a/Weeks/Week4.md
+++ b/Weeks/Week4.md
@@ -1,6 +1,24 @@
 ---
 title: Week 4
 layout: default
-parent: 2) Calender
-nav_order: 4
+parent: Calendar
+nav_order: 5
 ---
+
+# Week 4
+
+At the end of this week you will be able to: <br>
+Define and analyse numerical methods to solve systems governed by Partial Differential Equations in 2-dimensional domains. This entails:<br>
+<i>1. Define the system of PDEs that characterize the behaviour of linear elastic structures in 2D</i><br>
+<i>2. Define numerical methods to solve a system of PDEs</i> <br>
+<i>3. Implement a solver for a system of PDEs</i><br>
+<i>4. Analyse and justify the results</i><br>
+{: .learningobjectives }
+
+Week 4. Computational methods for time-dependent Partial Differential Equations in 2D [[pdf]](https://surfdrive.surf.nl/files/index.php/s/Jm8e95QGRS97bDq/download?path=%2FWeek4&files=4_1_Numerical_methods_for_PDEs_in%202D.pdf):<br>
+<i>1. Isoparametric mapping [2.8](https://teachbooks.tudelft.nl/computational-modelling/introduction/isoparametric mapping.html)</i> <br>
+<i>2. Numerical integration [2.6](https://teachbooks.tudelft.nl/computational-modelling/introduction/numerical_integration.html)</i> <br>
+{: .content }
+
+[Workshop 1](https://teachbooks.tudelft.nl/computational-modelling/contiuum_linear/Exercises/Workshop_FEM_Linear_Elasticity.html)<br>
+{: .exercises }
diff --git a/_modules/week-03.md b/_modules/week-03.md
index c14c73c..09f7c57 100644
--- a/_modules/week-03.md
+++ b/_modules/week-03.md
@@ -35,7 +35,7 @@ Week 3. Computational methods for time-dependent Partial Differential Equations
 <i>4. Theory: Space frames [4.3](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/space_frame.html)</i> <br>
 {: .content }
 
-[Workshop 6](https://teachbooks.tudelft.nl/computational-modelling/dynamics/Exercises/Workshop_FEM_dyn_rod.html)<br>
-[Workshop 7](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/Exercises/Workshop_FEM_dyn_beam.html)<br>
-[Workshop 8](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/Exercises/Workshop_FEM_dyn_space_frames.html)<br>
+[Workshop 1](https://teachbooks.tudelft.nl/computational-modelling/dynamics/Exercises/Workshop_FEM_dyn_rod.html)<br>
+[Workshop 2](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/Exercises/Workshop_FEM_dyn_beam.html)<br>
+[Workshop 3](https://teachbooks.tudelft.nl/computational-modelling/structural_linear/Exercises/Workshop_FEM_dyn_space_frames.html)<br>
 {: .exercises }
diff --git a/_modules/week-04.md b/_modules/week-04.md
new file mode 100644
index 0000000..59eb148
--- /dev/null
+++ b/_modules/week-04.md
@@ -0,0 +1,37 @@
+---
+title: "Week 4: Numerical methods for time-dependent Partial Differential Equations in 2D"
+---
+
+<!-- This will make a piece of text, followed by a button that is a hyperlink that opens in a new tab -->
+<!-- In-Class Session <a href="https://tudelft-citg.github.io/HOS-prob-design/homework/HW_05_assignment.html" target="_blank">HW 5 Due</a>{: .label .label-red } -->
+
+Lecture
+: Numerical methods for time-dependent PDEs in 2D
+  <br><em>Wednesday, 08:45-12:45, Flux Hall D</em>
+
+Homework
+: Study content of week 4
+
+Workshop
+: Workshop: FEM for Linear Elasticity
+  <br><em>Wednesday, 08:45-12:45, Flux Hall D</em>
+  <br><em>Thursday, 13:45-15:45, Flux Hall D</em>
+
+<!-- Holidays
+: None -->
+
+At the end of this week you will be able to: <br>
+Define and analyse numerical methods to solve systems governed by Partial Differential Equations in 2-dimensional domains. This entails:<br>
+<i>1. Define the system of PDEs that characterize the behaviour of linear elastic structures in 2D</i><br>
+<i>2. Define numerical methods to solve a system of PDEs</i> <br>
+<i>3. Implement a solver for a system of PDEs</i><br>
+<i>4. Analyse and justify the results</i><br>
+{: .learningobjectives }
+
+Week 4. Computational methods for time-dependent Partial Differential Equations in 2D [[pdf]](https://surfdrive.surf.nl/files/index.php/s/Jm8e95QGRS97bDq/download?path=%2FWeek4&files=4_1_Numerical_methods_for_PDEs_in%202D.pdf):<br>
+<i>1. Isoparametric mapping [2.8](https://teachbooks.tudelft.nl/computational-modelling/introduction/isoparametric mapping.html)</i> <br>
+<i>2. Numerical integration [2.6](https://teachbooks.tudelft.nl/computational-modelling/introduction/numerical_integration.html)</i> <br>
+{: .content }
+
+[Workshop 1](https://teachbooks.tudelft.nl/computational-modelling/contiuum_linear/Exercises/Workshop_FEM_Linear_Elasticity.html)<br>
+{: .exercises }
diff --git a/calendar.md b/calendar.md
index 5146db5..fd7c6f6 100644
--- a/calendar.md
+++ b/calendar.md
@@ -15,6 +15,7 @@ The topics covered in each week are:
 - Week 1: Computational Methods for ODEs
 - Week 2: Computational methods for rigid body dynamics
 - Week 3: Computational methods for Partial Differential Equations
+- Week 4: Computational methods for Partial Differential Equations in 2D
 
 <!-- - Week 2:
 - Week 3:
@@ -22,4 +23,4 @@ The topics covered in each week are:
 - Week 5:
 - Week 6:
 - Week 7:
-- Week 8: -->
\ No newline at end of file
+- Week 8: -->