diff --git a/MatrixBerechnung.ods b/MatrixBerechnung.ods
new file mode 100644
index 0000000..fbbf201
Binary files /dev/null and b/MatrixBerechnung.ods differ
diff --git a/goodcalc.go b/goodcalc.go
index 1fff7d2..4c53256 100644
--- a/goodcalc.go
+++ b/goodcalc.go
@@ -1,42 +1,69 @@
 // Package goodcalc is a good balance calculator
+// The logic of the calculation is based on the
+// excel calculator. The simple steps can be found
+// inside the MatrixBerechnung.ods file inside this
+// repository.
 package goodcalc
 
+// Matrix contains the stakeholders and the maximal
+// allowed points of the calculation. The calculation
+// is pretty simple. Inside each aspect ValuationPoints
+// can be defined. Over the maximal possible points
+// the balancePoints are calculated.
+//
+// It is possible to define different weights on different
+// layers (stakeholder, theme and aspect).
+// This type does not contain any businesslogic of the version
+// of the matrix.
 type Matrix struct {
-	MaxPoints    int
-	Stakeholders []Stakeholder
+	MaxPoints    int           `json:"max_points,omitempty"`
+	Stakeholders []Stakeholder `json:"stakeholders,omitempty"`
 }
 
+// Stakeholder can define a weight, which is calculated to
+// all containing themes.
+// No is the id like in the excel
+// For example A for Suppliers
 type Stakeholder struct {
-	No     string
-	Weight float32
+	No     string  `json:"no,omitempty"`
+	Weight float32 `json:"weight,omitempty"`
+	Themes []Theme `json:"themes,omitempty"`
 }
 
+// Theme is the basic element of the matrix.
+// No defines the id of the excel balance.
+// A1 for Human dignity in the supply chain
 type Theme struct {
-	No              string
-	Weight          float32
-	Aspects         []Aspect
-	NegativeAspects []NegativeAspect
-	ThemeCalc       // calculatet values
+	No              string           `json:"no,omitempty"`
+	Weight          float32          `json:"weight,omitempty"`
+	Aspects         []Aspect         `json:"aspects,omitempty"`
+	NegativeAspects []NegativeAspect `json:"negative_aspects,omitempty"`
+	Calculation     ThemeCalc        `json:"calculation,omitempty"`
 }
 
+// Aspect does contain the valuation of the company.
 type Aspect struct {
-	No     string
-	Weight float32
-	Points int
+	No              string  `json:"no,omitempty"`
+	Weight          float32 `json:"weight,omitempty"`
+	ValuationPoints int     `json:"valuation_points,omitempty"`
 }
 
+// NegativeAspect has the same fields like Aspect. But the
+// business logic requieres a different handling.
 type NegativeAspect struct {
 	Aspect
 }
 
+// ThemeCalc contains the different calculation
+// steps.
 type ThemeCalc struct {
-	CalcWeight              float32
-	WeightFactor            float32
-	MaxPoints               float32
-	NrPositiveAspects       int
-	ValuationPoints         int
-	EstPercentage           float32
-	blancePoints            int
-	NegativeValuationPoints int
-	NegativeBlancePoints    int
+	CalcWeight              float32 `json:"calc_weight,omitempty"`
+	WeightFactor            float32 `json:"weight_factor,omitempty"`
+	MaxPoints               float32 `json:"max_points,omitempty"`
+	NrPositiveAspects       int     `json:"nr_positive_aspects,omitempty"`
+	ValuationPoints         int     `json:"valuation_points,omitempty"`
+	EstPercentage           float32 `json:"est_percentage,omitempty"`
+	BalancePoints           int     `json:"balance_points,omitempty"`
+	NegativeValuationPoints int     `json:"negative_valuation_points,omitempty"`
+	NegativeBlancePoints    int     `json:"negative_blance_points,omitempty"`
 }