diff --git a/src/database.rs b/src/database.rs
index bc1345f..ec7603f 100644
--- a/src/database.rs
+++ b/src/database.rs
@@ -1,8 +1,8 @@
+// SPDX-License-Identifier: 0BSD, MIT
 /*
  * advotracker - Hotline tackingtool for Advocats
  *
- * Copyright 2019 Ralf Zerres <ralf.zerres@networkx.de>
- * SPDX-License-Identifier: (0BSD or MIT)
+ * Copyright 2020-2021 Ralf Zerres <ralf.zerres@networkx.de>
  */
 
 // module: db
diff --git a/src/lib.rs b/src/lib.rs
index a51e272..1fa1008 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,8 +1,8 @@
+// SPDX-License-Identifier: 0BSD, MIT
 /*
  * advotracker - Hotline tackingtool for Advocats
  *
- * Copyright 2020 Ralf Zerres <ralf.zerres@networkx.de>
- * SPDX-License-Identifier: 0BSD, MIT
+ * Copyright 2020-2021 Ralf Zerres <ralf.zerres@networkx.de>
  */
 
 #![warn(missing_docs, rust_2018_idioms, rust_2018_compatibility)]
@@ -38,6 +38,6 @@ mod tests {
 
     #[test]
     fn internal_test() {
-	assert_eq!(8, internal_adder(4, 4));
+        assert_eq!(8, internal_adder(4, 4));
     }
 }
diff --git a/src/main.rs b/src/main.rs
index abd61a5..925f1ed 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,7 +1,8 @@
-/* advotracker infrastructure.
+// SPDX-License-Identifier: 0BSD, MIT
+/*
+ * advotracker - Hotline tackingtool for Advocats
  *
- * Copyright 2020 Ralf Zerres <ralf.zerres@networkx.de>
- * SPDX-License-Identifier: (0BSD or MIT)
+ * Copyright 2020-2021 Ralf Zerres <ralf.zerres@networkx.de>
  */
 
 // Rust nightly supports procedural macros!
@@ -51,9 +52,9 @@ impl AdvoTrackerSubscriber {
 fn run_subcommand(matches: &ArgMatches) -> Result<(), String> {
     //info!("inside run_subcommand");
     match matches.subcommand() {
-	("config", Some(cmd)) => run_config(cmd),
-	("test", Some(cmd)) => run_test(cmd),
-	_ => Ok(()),
+        ("config", Some(cmd)) => run_config(cmd),
+        ("test", Some(cmd)) => run_test(cmd),
+        _ => Ok(()),
     }
 }
 
@@ -68,11 +69,11 @@ fn run_test(matches: &ArgMatches)  -> Result<(), String> {
     //info!("inside run_test");
 
     if let Some(matches) = matches.subcommand_matches("test") {
-	if matches.is_present("debug") {
-	    println!("test: Printing debug info...");
-	} else {
-	    println!("test: Printing normally...");
-	}
+        if matches.is_present("debug") {
+            println!("test: Printing debug info...");
+        } else {
+            println!("test: Printing normally...");
+        }
     }
     Ok(())
 }
@@ -95,8 +96,8 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     let span = tracing::span!(Level::TRACE, "advotracker_main");
     let _enter = span.enter();
     let subscriber = fmt::Subscriber::builder()
-	.with_env_filter("advotracker=trace")
-	.finish();
+        .with_env_filter("advotracker=trace")
+        .finish();
 
     // initialize logger
     // TODO: exchange with tracing!
@@ -104,109 +105,109 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     //info!("Commencing the proxy!");
 
     tracing::subscriber::with_default(subscriber, || {
-	// get system environment
-	let mut lang = env::var("LANG").unwrap_or("en".to_string());
-	let mut res = t!("parse.environment", lang);
-	let mut state = t!("state.started", lang);
-	trace!(target: "advotracker", message = ?res, state = ?state);
-	//debug!(message = ?res, state = ?state);
-	trace!(target: "advotracker", environment = "system", lang = ?lang);
+        // get system environment
+        let mut lang = env::var("LANG").unwrap_or("en".to_string());
+        let mut res = t!("parse.environment", lang);
+        let mut state = t!("state.started", lang);
+        trace!(target: "advotracker", message = ?res, state = ?state);
+        //debug!(message = ?res, state = ?state);
+        trace!(target: "advotracker", environment = "system", lang = ?lang);
 
-	// get testing environment (.env)
-	dotenv().ok();
-	match envy::from_env::<Environment>() {
-	    Ok(environment) => {
-		if environment.test_lang != lang { lang = environment.test_lang; }
-	    },
-	    Err(e) => { debug!(target: "advotracker", "{}", e); }
-	}
-	res = t!("parse.environment", lang);
-	trace!(target: "advotracker", environment = "envy", lang = ?lang);
-	state = t!("state.finished", lang);
-	trace!(target: "advotracker", message = ?res, state = ?state);
-	//debug!(message = ?res, state = ?state);
+        // get testing environment (.env)
+        dotenv().ok();
+        match envy::from_env::<Environment>() {
+            Ok(environment) => {
+                if environment.test_lang != lang { lang = environment.test_lang; }
+            },
+            Err(e) => { debug!(target: "advotracker", "{}", e); }
+        }
+        res = t!("parse.environment", lang);
+        trace!(target: "advotracker", environment = "envy", lang = ?lang);
+        state = t!("state.finished", lang);
+        trace!(target: "advotracker", message = ?res, state = ?state);
+        //debug!(message = ?res, state = ?state);
 
-	// initialize viperus structure
-	let mut v = Viperus::new();
+        // initialize viperus structure
+        let mut v = Viperus::new();
 
-	// parse commandline arguments
-	res = t!("parse.arguments", lang);
-	state = t!("state.started", lang);
-	trace!(target: "advotracker", process = ?res, state = ?state);
-	//info!(target: "advotracker", "{}", res);
-	//debug!(message = ?res, state = ?state);
-	//info!(target: "advotracker", "parsing commandline args");
-	let _ = parse_args(&mut v);
-	state = t!("state.finished", lang);
-	trace!(target: "advotracker", process = ?res, state = ?state);
-	//trace!(target: "Viperus", "Config results: {:?}", v);
+        // parse commandline arguments
+        res = t!("parse.arguments", lang);
+        state = t!("state.started", lang);
+        trace!(target: "advotracker", process = ?res, state = ?state);
+        //info!(target: "advotracker", "{}", res);
+        //debug!(message = ?res, state = ?state);
+        //info!(target: "advotracker", "parsing commandline args");
+        let _ = parse_args(&mut v);
+        state = t!("state.finished", lang);
+        trace!(target: "advotracker", process = ?res, state = ?state);
+        //trace!(target: "Viperus", "Config results: {:?}", v);
 
-	/*
-	if verbose > 1 {
-	    for (key, value) in env::vars() {
-		println!("{}={}", key, value);
-	    }
-	}
-	 */
+        /*
+        if verbose > 1 {
+            for (key, value) in env::vars() {
+                println!("{}={}", key, value);
+            }
+        }
+         */
 
-	//state = t!("state.finished", lang);
-	//trace!(target: "advotracker", process = ?res, state = ?state);
-	//debug!(message = ?res, state = ?state);
+        //state = t!("state.finished", lang);
+        //trace!(target: "advotracker", process = ?res, state = ?state);
+        //debug!(message = ?res, state = ?state);
 
-	/*
-	// handle subcommands
-	if let Err(e) = run_subcommand(&matches) {
-	    println!("Subcommand error: {}", e);
-	    process::exit(1);
-	}
-	 */
+        /*
+        // handle subcommands
+        if let Err(e) = run_subcommand(&matches) {
+            println!("Subcommand error: {}", e);
+            process::exit(1);
+        }
+         */
 
-	// Starting the program logic
-	res = t!("main.started", lang);
-	state = t!("state.started", lang);
-	//info!(target: "advotracker", "{}", res);
-	trace!(target: "advotracker", process = ?res, state = ?state);
+        // Starting the program logic
+        res = t!("main.started", lang);
+        state = t!("state.started", lang);
+        //info!(target: "advotracker", "{}", res);
+        trace!(target: "advotracker", process = ?res, state = ?state);
 
-	//use advotracker_backend::*;
-	//use advotracker_backend::schema::users::dsl::*;
+        //use advotracker_backend::*;
+        //use advotracker_backend::schema::users::dsl::*;
 
-	/*
-	let connection = establish_connection();
+        /*
+        let connection = establish_connection();
 
-	trace!(
-	    target: "advotracker",
-	    process = "Sqlite3",
-	    status = "connected",
-	);
-	 */
+        trace!(
+            target: "advotracker",
+            process = "Sqlite3",
+            status = "connected",
+        );
+         */
 
-	/*
-	//User::table.load(&connection);
-	//user::belonging_to(users).load(&connection);
-	use advotracker_backend::models::*;
+        /*
+        //User::table.load(&connection);
+        //user::belonging_to(users).load(&connection);
+        use advotracker_backend::models::*;
 
 
-	let results = users
-	    //.filter(published.eq(true))
-	    .limit(5)
-	    .load::<User>(&connection)
-	    .expect("Error loading users");
+        let results = users
+            //.filter(published.eq(true))
+            .limit(5)
+            .load::<User>(&connection)
+            .expect("Error loading users");
 
-	println!("Displaying {} users", results.len());
-	for user in results {
-	    println!("{}", user.user_id);
-	    println!("----------\n");
-	    println!("{}", user.first_name);
-	    println!("{}", user.last_name);
-	    println!("{}", user.alias);
-	    println!("{}", user.email);
-	}
-	 */
+        println!("Displaying {} users", results.len());
+        for user in results {
+            println!("{}", user.user_id);
+            println!("----------\n");
+            println!("{}", user.first_name);
+            println!("{}", user.last_name);
+            println!("{}", user.alias);
+            println!("{}", user.email);
+        }
+         */
 
-	state = t!("state.finished", lang);
-	res = t!("main.finished", lang);
-	//info!(target: "advotracker", "{}", res);
-	trace!(target: "advotracker", process = ?res, state = ?state);
+        state = t!("state.finished", lang);
+        res = t!("main.finished", lang);
+        //info!(target: "advotracker", "{}", res);
+        trace!(target: "advotracker", process = ?res, state = ?state);
     });
 
     Ok(())
diff --git a/src/parse_args.rs b/src/parse_args.rs
index b7e896c..ac9071d 100644
--- a/src/parse_args.rs
+++ b/src/parse_args.rs
@@ -1,7 +1,8 @@
-/* advotracker infrastructure.
+// SPDX-License-Identifier: 0BSD, MIT
+/*
+ * advotracker - Hotline tackingtool for Advocats
  *
- * Copyright 2020 Ralf Zerres <ralf.zerres@networkx.de>
- * SPDX-License-Identifier: (0BSD or MIT)
+ * Copyright 2020-2021 Ralf Zerres <ralf.zerres@networkx.de>
  */
 
 use viperus::Viperus;
diff --git a/tests/integration_test.rs b/tests/integration_test.rs
index 9d925a2..f643d71 100644
--- a/tests/integration_test.rs
+++ b/tests/integration_test.rs
@@ -1,7 +1,13 @@
+// SPDX-License-Identifier: 0BSD, MIT
+/*
+ * advotracker - Hotline tackingtool for Advocats
+ *
+ * Copyright 2020-2021 Ralf Zerres <ralf.zerres@networkx.de>
+ */
+
 //use advotracker;
 
 #[test]
 fn integration_add_two() {
     assert_eq!(4, advotracker_backend::add_two(2));
 }
-