End-to-end encryption and privacy controls.
Message and call for free* around the world.
Group conversations made simple.
Say it with stickers, voice, GIFs and more.
Reach your customers from anywhere.
http://mahmood.farafile.ir/file/47184/جزوه-دست-نویس-معادلات-دیفرانسیل-–استاد-پورنکی(دانشگاه-شریف)