IMPLEMEMENT A NEW FONT

Trying to implement the Bookman Old Style regular font to my site using the following code. However, it will not work. Any advice on this?

Thanks 

// CUSTOM FONT

@font-face {

font-family: BOOKMAN OLD STYLE REGULAR'';

src: url(https://static1.squarespace.com/static/65afe66b9383ee2d09db1955/t/65b189116ca34539e52951ea/1706133777646/Bookman+Old+Style+Regular.ttf);

}

h1 {

font-family: 'BOOKMAN OLD STYLE REGULAR';}

h2 {

font-family: 'BOOKMAN OLD STYLE REGULAR';}

h3 {

font-family: 'BOOKMAN OLD STYLE REGULAR';}

h4 {

font-family: 'BOOKMAN OLD STYLE REGULAR';}

.sqsrte-large {

font-family: 'BOOKMAN OLD STYLE REGULAR';}

p {

font-family: 'BOOKMAN OLD STYLE REGULAR';}

.sqsrte-small {

font-family: 'BOOKMAN OLD STYLE REGULAR';}

Remove this double symbol