Getting Started with the Arduino GSM Shield | Arduino Documentation | Arduino Documentation
How to use GSM For SMS Send Receive and Call - Hackster.io
SIM900 GPRS/GSM Schild Development Board Quad Band Modul für arduino Kompatibel mit MEGA 2560 850/900/1800/1900 MHz|gprs/gsm shield|module for arduinosim900 gprs/gsm shield - AliExpress
SIM7000E GSM Modul LTE B3 B8 B20 B28 eMTC NB-IoT EU Netzwerk für Arduino | eBay
Interfacing GSM Modem with Arduino Uno - Tutorial - Sending SMS