<<elegos made an interesting point about tennis magazines in central europe not being published after the first world war. do you by any chance know of any pre-war magazines in german language?>>
I'm not sure whether any tennis magazines were published in Central Europe between 1919 and 1939. As for the years before 1914, the German publication "Der Lawn-Tennis-Sport" was published from about 1904 to 1908; this was followed by "Lawn-Tennis und Golf", which was published until about 1916. Newspapers and sports publications such as "Die Neue Sportwoche" and "Sport und Spiel" also covered lawn tennis regularly. Most of these are availabe in the Sporthochschule in Cologne and the German National Library in Leipzig.
There were also yearbooks in German before World War One, possibly not just covering lawn tennis in Germany. These were definitely published again in the interwar years; also in Austria and Switzerland. I thought "Lawn-Tennis und Golf" was published again after World War One, but would have to check that.
"Der Rasensport" (circa 1900-29) is probably also a good source for lawn tennis results and other related information, but it features other sports too, especially football.
Here are a couple of related German-language links: