diff --git a/backend/src/controller/classroom/mod.rs b/backend/src/controller/classroom/mod.rs
index a19e316..2548112 100644
--- a/backend/src/controller/classroom/mod.rs
+++ b/backend/src/controller/classroom/mod.rs
@@ -20,16 +20,16 @@ pub async fn create_user(
     data: Json<ClassroomPersonCreate>,
 ) -> (Status, Json<JsonResult<PersonLink>>) {
     match create(&data.0).await {
-        Ok(p) => return (Status::Ok, JsonResult::ok(p)),
-        Err(err) => return (Status::InternalServerError, JsonResult::err(err)),
+        Ok(p) => (Status::Ok, JsonResult::ok(p)),
+        Err(err) => (Status::InternalServerError, JsonResult::err(err)),
     }
 }
 
 #[get("/classroom/course/<user_id>")]
 pub async fn get_courses(user_id: i32) -> (Status, Json<JsonResult<Vec<ClassroomCourse>>>) {
     match crate::online_classroom::get_courses::get_courses(user_id).await {
-        Ok(courses) => return (Status::Ok, JsonResult::ok(courses)),
-        Err(err) => return (Status::InternalServerError, JsonResult::err(err)),
+        Ok(courses) => (Status::Ok, JsonResult::ok(courses)),
+        Err(err) => (Status::InternalServerError, JsonResult::err(err)),
     }
 }
 
@@ -44,16 +44,16 @@ pub async fn register_course_contr(
     data: Json<ClassroomCourseRegistration>,
 ) -> (Status, Json<JsonResult<()>>) {
     match register_course(user_id, &data.surname_first_letter, &data.courses).await {
-        Ok(()) => return (Status::Ok, JsonResult::ok(())),
-        Err(err) => return (Status::InternalServerError, JsonResult::err(err)),
+        Ok(()) => (Status::Ok, JsonResult::ok(())),
+        Err(err) => (Status::InternalServerError, JsonResult::err(err)),
     }
 }
 
 #[get("/classroom/expiration_date/<user_id>")]
 pub async fn get_expiration_date(user_id: i32) -> (Status, Json<JsonResult<String>>) {
     match crate::online_classroom::get_expiration_date::get_expiration_date(user_id).await {
-        Ok(date) => return (Status::Ok, JsonResult::ok(date)),
-        Err(err) => return (Status::InternalServerError, JsonResult::err(err)),
+        Ok(date) => (Status::Ok, JsonResult::ok(date)),
+        Err(err) => (Status::InternalServerError, JsonResult::err(err)),
     }
 }
 
@@ -81,7 +81,7 @@ pub async fn set_expiration_date(
     data: Json<ExpirationDate>,
 ) -> (Status, Json<JsonResult<()>>) {
     match update_expiration_date(user_id, data.date.clone()).await {
-        Ok(()) => return (Status::Ok, JsonResult::ok(())),
-        Err(err) => return (Status::InternalServerError, JsonResult::err(err)),
+        Ok(()) => (Status::Ok, JsonResult::ok(())),
+        Err(err) => (Status::InternalServerError, JsonResult::err(err)),
     }
 }
diff --git a/backend/src/controller/register/mod.rs b/backend/src/controller/register/mod.rs
index 844ab78..f390323 100644
--- a/backend/src/controller/register/mod.rs
+++ b/backend/src/controller/register/mod.rs
@@ -33,7 +33,7 @@ pub async fn insert_all(data: Json<Vec<RegisterCreate>>) -> (Status, Json<JsonRe
 }
 
 #[get("/register/<dni>")]
-pub async fn get_by_dni(dni: i32) -> (Status, Json<JsonResult<Vec<Register>>>) {
+pub async fn get_by_dni(dni: String) -> (Status, Json<JsonResult<Vec<Register>>>) {
     let registers = Register::get_by_dni(dni).await;
 
     match registers {
diff --git a/backend/src/model/register.rs b/backend/src/model/register.rs
index b3c8888..50d40ed 100644
--- a/backend/src/model/register.rs
+++ b/backend/src/model/register.rs
@@ -88,7 +88,7 @@ impl RegisterCreate {
         } else {
             let res = sqlx::query!(
                 "SELECT MAX(register_code) AS max FROM register
-                WHERE register_course_id = '?'",
+                WHERE register_course_id=?",
                 course_id
             )
             .fetch_one(db)
@@ -126,7 +126,7 @@ pub struct Register {
 }
 
 impl Register {
-    pub async fn get_by_dni(dni: i32) -> Result<Vec<Register>, sqlx::Error> {
+    pub async fn get_by_dni(dni: String) -> Result<Vec<Register>, sqlx::Error> {
         let db = db();
 
         let res = sqlx::query!(
diff --git a/frontend/src/certGenerator/certs/PRIMEROS_AUXILIOS.ts b/frontend/src/certGenerator/certs/PRIMEROS_AUXILIOS.ts
index 5bff780..955da7e 100644
--- a/frontend/src/certGenerator/certs/PRIMEROS_AUXILIOS.ts
+++ b/frontend/src/certGenerator/certs/PRIMEROS_AUXILIOS.ts
@@ -73,7 +73,7 @@ const tTopics = createSimpleText({
     yPosition: 9.4,
     width: 20.92,
     height: 1.5,
-    text: "En temas de: Tres Reglas de Seguridad Básicas (S.S.S.), Primeros Auxilios Psicológico, Inicio de la Cadena de Vida, RCP, Hemorragias Quemaduras, Fracturas, uso de férulas y vendajes, Maniobra de Heimlich, Traslado de Pacientes, Posición lateral de Seguridad PLS, Tratamientos por intoxicación asfixia o ahogamiento, Practicas en Técnicas de Control de Primeros Auxilios, equivalente a 04 horas lectivas.",
+    text: "En temas de: Tres Reglas de Seguridad Básicas (S.S.S.), Primeros Auxilios Psicológico, Inicio de la Cadena de Vida, RCP, Hemorragias Quemaduras, Fracturas, uso de férulas y vendajes, Maniobra de Heimlich, Traslado de Pacientes, Posición lateral de Seguridad PLS, Tratamientos por intoxicación asfixia o ahogamiento, Practicas en Técnicas de Control de Primeros Auxilios, equivalente a 12 horas lectivas.",
     size: 22,
     font: "Times New Roman",
     alignment: AlignmentType.LEFT,