diff --git a/src/components/Buttons.tsx b/src/components/Buttons.tsx
index 69f5036e44b5a2b0f8b56a89d0ac853bb6160676..e1ac22d55dd0aadd8419d37c279d3376bd8a7b6c 100644
--- a/src/components/Buttons.tsx
+++ b/src/components/Buttons.tsx
@@ -114,7 +114,7 @@ return (
 
 
 export function TabButtonRow({data, classy, opentype, closing}: {data: Array<TabDatensatz>, classy?: string, opentype: string, closing: string}){
-  let rows = []
+  let rows: JSX.Element[]  = []
   for ( let i = 0;  i < data.length; i++ ){
     if(classy){
       rows.push(<TabButton classy={classy} type={data[i].cssname} name={data[i].buttonname} opentype={opentype} closing={closing}/>)
diff --git a/src/components/Headings.tsx b/src/components/Headings.tsx
index 66d8cb7d2d935a4da91d5c3a25afca981db79174..dbcf1fac633fa3bbc8d1b6bce30e9b9e6f1b8990 100644
--- a/src/components/Headings.tsx
+++ b/src/components/Headings.tsx
@@ -1,7 +1,7 @@
 import { stringToSlug } from "../utils";
 
 export function Hhopp({text, id}:{text: string, id?: string}){
-    const arr = []; 
+    const arr: JSX.Element[]  = []; 
     var idtext: string; 
     if (id) {
         idtext = id; 
@@ -21,7 +21,7 @@ export function Hhopp({text, id}:{text: string, id?: string}){
 }
 
 export function Hsmoke({text, id}:{text: string, id?: string}){
-    const arr = []; 
+    const arr: JSX.Element[]  = []; 
     var idtext: string; 
     if (id) {
         idtext = id; 
diff --git a/src/components/HorizontalTimeline.tsx b/src/components/HorizontalTimeline.tsx
index ec334623ca67c86a9907e59056ac76ea4c0a5797..b2e264d0ac9d8af7d8d44d1e5d41053e885b77c4 100644
--- a/src/components/HorizontalTimeline.tsx
+++ b/src/components/HorizontalTimeline.tsx
@@ -119,7 +119,7 @@ function TimeItem({tag, title, pic, author, tabid}: ItemProps){
 
 
       function AllItems(){
-        let rows = []
+        let rows: JSX.Element[]  = []
         for ( let i = 0;  i < timelinedata.length; i++ ){
           if (timelinedata[i].type === "meta"){
             var name: string; 
@@ -164,7 +164,7 @@ function TimeItem({tag, title, pic, author, tabid}: ItemProps){
 
       
       export function getItemsByType(tabid: string) {
-        let rows = []
+        let rows: JSX.Element[]  = []
         for (let i = 0; i < timelinedata.length; i++) {
             if (tabid === timelinedata[i].tag) {
               var name: string; 
diff --git a/src/components/Photo-grid.tsx b/src/components/Photo-grid.tsx
index 67169c23221c6fe0b309c3b5e616a2ed910a4af0..5f2820d69cc38fc2d76e2bf98d40f2307541e366 100644
--- a/src/components/Photo-grid.tsx
+++ b/src/components/Photo-grid.tsx
@@ -42,7 +42,7 @@ const images = [
 
 
 export default function BFHGallery(){
-  let rows = []
+  let rows: JSX.Element[]  = []
   for ( let i = 0;  i < images.length; i++ ){
     rows.push(<div><img src={images[i].src}/></div>) 
   }
diff --git a/src/components/Sidebar.tsx b/src/components/Sidebar.tsx
index f4aa5a5696b03a867161a58db3cacdafa8a6516e..ad3d3ada56f32d952f48dba391ec9ddb8b839748 100644
--- a/src/components/Sidebar.tsx
+++ b/src/components/Sidebar.tsx
@@ -63,7 +63,7 @@ function Sidebar(){
       
 
         console.log(nums)
-        let content = []; 
+        let content: JSX.Element[]  = []; 
         for(let idx in nums){
             const item = nums[idx];
             /* console.log("idx: " + idx);
diff --git a/src/components/Table.tsx b/src/components/Table.tsx
index ee88868bdba213cb83db7e9bc515339268c4ab23..6770df8d942407ffa9c82b8e361057ce358d5fda 100644
--- a/src/components/Table.tsx
+++ b/src/components/Table.tsx
@@ -1,7 +1,7 @@
 import { Part } from "../data/parts";
 
 export function PartTable({data, cols}: {data: Array<Part>, cols: Array<string>}){
-    let list = [];
+    let list: JSX.Element[]  = [];
     for (let index = 0; index < data.length; index++) {
         list.push(
             <tr>
@@ -13,7 +13,7 @@ export function PartTable({data, cols}: {data: Array<Part>, cols: Array<string>}
             </tr>
         )
     }
-    let heads = []; 
+    let heads: JSX.Element[]  = []; 
     for (let index = 0; index < cols.length; index++) {
         heads.push(<td><b>{cols[index]}</b></td>)
     }
diff --git a/src/components/Tabs.tsx b/src/components/Tabs.tsx
index 2327c157f1d6a3d3fe075708587751536c6ade8a..e0df0e51e4ef98d3c014dabca5f93f5aa698f2a8 100644
--- a/src/components/Tabs.tsx
+++ b/src/components/Tabs.tsx
@@ -1,6 +1,6 @@
 // The main tab has to be given display: block; via id css or be given the id "First"
 export function ButtonRowTabs({data, cla}: {data: Array<TabDatensatz>, cla: string}) {
-    let rows = []
+    let rows: JSX.Element[]  = []
     for ( let i = 0;  i < data.length; i++ ){
       if(data[i].main == true){
         rows.push(<div id={data[i].cssname} className={cla} style={{display: "block"}}>
@@ -24,7 +24,7 @@ import Collapsible from "./Collapsible";
 /* import { stringToSlug } from "../utils"; */
   
   export function BFHStyleTabs({data, cla}: {data: Array<TimelineDatenpunkt>, cla: string}) {
-    let rows = []
+    let rows: JSX.Element[]  = []
     for ( let i = 0;  i < data.length; i++ ){
       var problem: Boolean = false; 
       var problem_desc: Array<string> = [];
@@ -250,7 +250,7 @@ import Collapsible from "./Collapsible";
   /* Interview */
  
   export function OLDBFHStyleTabs({data, cla}: {data: Array<NodeDatensatz>, cla: string}) {
-    let rows = []
+    let rows: JSX.Element[]  = []
     for ( let i = 0;  i < data.length; i++ ){
       if (data[i].cssname == "timeline"){
         rows.push(
diff --git a/src/contents/Contribution/Wiki/Filterables.tsx b/src/contents/Contribution/Wiki/Filterables.tsx
index 8b0d913e72bd280b6847a9cfef77a5dfa8182f03..2b41d790eca43fe786f2f4d631058288e24fe482 100644
--- a/src/contents/Contribution/Wiki/Filterables.tsx
+++ b/src/contents/Contribution/Wiki/Filterables.tsx
@@ -5,7 +5,7 @@ import { Troubleshoot } from "./trouble-data";
 
 export function Filterables(data: Array<Troubleshoot>){
     let count = 2; 
-    let results = [];
+    let results: JSX.Element[]  = [];
     for (let index = 0; index < data.length; index++) {
         let tags = ""
         for (let i = 0; i < data[index].tags.length; i++) {
diff --git a/src/contents/methods.tsx b/src/contents/methods.tsx
index 13a28bf897b4f097cab4e1486b360d513cc998be..9e3421940efc2cdc1e15465b4965e022c68b5339 100644
--- a/src/contents/methods.tsx
+++ b/src/contents/methods.tsx
@@ -1,7 +1,6 @@
 import { Section, Subesction } from "../components/sections";
 import { useTabNavigation } from "../utils/TabNavigation";
 import {H5} from "../components/Headings";
-import TestSource from "../sources/test-sources";
 import MethodSources from "../sources/methods-sources";
 
 export function Methods() {
diff --git a/src/contents/team.tsx b/src/contents/team.tsx
index 87ed6412ea4b8cf803633a836ecb3a9d6b617459..0d0aa1c3ed811c68b8fc4a6c89f60240f3c72eef 100644
--- a/src/contents/team.tsx
+++ b/src/contents/team.tsx
@@ -36,7 +36,7 @@ export function Team() {
 
 
 function createSteckbriefe(data: Array<SteckbriefInterface>){
-  let briefe = []
+  let briefe: JSX.Element[]  = []
   for (let index = 0; index < data.length; index++) {
     let thename = "" + data[index].vorname + data[index].nachname; 
     // Conditional head of
@@ -62,7 +62,7 @@ function createSteckbriefe(data: Array<SteckbriefInterface>){
         }
     }
     // Funfacts 
-    var funfacts = [];
+    var funfacts: JSX.Element[]  = [];
     for (let i = 0; i < data[index].funfacts.length; i++) {
       funfacts.push(<li key={`f${i}`}> {data[index].funfacts[i]} </li>); 
     }
@@ -83,7 +83,7 @@ function createSteckbriefe(data: Array<SteckbriefInterface>){
       }
     }
     // Whyigem
-    var why = []; 
+    var why: JSX.Element[]  = []; 
     for (let i = 0; i < data[index].whyigem.length; i++) {
       why.push(<p>{data[index].whyigem[i]}</p>); 
     }
@@ -93,12 +93,12 @@ function createSteckbriefe(data: Array<SteckbriefInterface>){
       title = data[index].title!; 
     }
     // challenges
-    let challs = [];  
+    let challs: JSX.Element[]  = [];  
     for (let i = 0; i < data[index].biggestchallenge.length; i++) {
       challs.push(<li key={`d${i}`}>{data[index].biggestchallenge[i]}</li>); 
     }
     // bestparts
-    let bests = [];  
+    let bests: JSX.Element[]  = [];  
     for (let i = 0; i < data[index].bestpart.length; i++) {
       bests.push(<li key={`e${i}`}>{data[index].bestpart[i]}</li>); 
     }
@@ -140,7 +140,7 @@ function createSteckbriefe(data: Array<SteckbriefInterface>){
 }
 
 function createPiSteckbriefe(data: Array<SteckbriefInterface>){
-  let briefe = []
+  let briefe: JSX.Element[]  = []
   for (let index = 0; index < data.length; index++) {
     let thename = "" + data[index].vorname + data[index].nachname; 
     // Conditional head of
@@ -159,7 +159,7 @@ function createPiSteckbriefe(data: Array<SteckbriefInterface>){
         }
     }
     // Funfacts 
-    var funfacts = [];
+    var funfacts: JSX.Element[]  = [];
     for (let i = 0; i < data[index].funfacts.length; i++) {
       funfacts.push(<li key={`a${i}`}> {data[index].funfacts[i]} </li>); 
     }
@@ -178,7 +178,7 @@ function createPiSteckbriefe(data: Array<SteckbriefInterface>){
       }
     }
     // Whyigem
-    var why = []; 
+    var why: JSX.Element[]  = []; 
     for (let i = 0; i < data[index].whyigem.length; i++) {
       why.push(<p>{data[index].whyigem[i]}</p>); 
     }
@@ -188,12 +188,12 @@ function createPiSteckbriefe(data: Array<SteckbriefInterface>){
       title = data[index].title!; 
     }
     // challenges
-    let challs = [];  
+    let challs: JSX.Element[]  = [];  
     for (let i = 0; i < data[index].biggestchallenge.length; i++) {
       challs.push(<li key={`b${i}`}>{data[index].biggestchallenge[i]}</li>); 
     }
     // bestparts
-    let bests = [];  
+    let bests: JSX.Element[]  = [];  
     for (let i = 0; i < data[index].bestpart.length; i++) {
       bests.push(<li key={`c${i}`}>{data[index].bestpart[i]}</li>); 
     }